Secret Agent "X" – The Complete Series, Volume 3

Satan’s signals! Those were the lights that gleamed above a bandit pack. Death’s own will-o’-the-wisps, with the power of an unseen curse behind them — a curse that made the police stand off, and made Secret Agent “X” pledge himself to battle on the volcano brink of destruction!

Chapter I

THE great plate-glass windows of Jules Pierrot’s Jewelry Shop cracked, split and snapped in a dozen places. Jagged, star-shaped holes appeared. Long slivers of shimmering glass broke away and fell to the sidewalk in a jangling cascade. Near the curb, six masked men, just emerging from a parked sedan, advanced slowly, laying a barrage of bullets before them.

Pedestrians in front of the fashionable store scattered and fled like frightened rabbits. They ducked for cover, sought shelter wherever they could find it.

A girl in expensive clothing, with silver fox furs draped over one shapely shoulder, ran like a mad thing close to the building’s facade. She passed near one of the masked bandits. Something gleamed at her white throat; something that caught the rays of the weak winter sun and sent out prismatic colors. It was a big diamond bar pin.

The bandit snarled in his throat like a hungry wolf. He grabbed the girl’s slim arm. His hooked fingers flashed forward, closing over the diamond. He ripped savagely, and the front of the girl’s dress tore open as the clasp of gold came loose. The bandit pushed her roughly away. She stumbled, fell to her silken knees, then leaped away again and dashed on, screaming fearfully, her high heels clicking over the pavement. The bandit pocketed the precious gem.

Others were already reaching through the shattered windows, scooping the glittering stones from the display racks. The leader of the vicious, marauding gang and one lieutenant, entered the store. Frightened customers, paralyzed with the sound of the din outside and the whining bullets that had glanced through the shop, huddled against counters. Clerks stood white-faced, trembling.

While the gunman guard crouched, with feet apart, the black snout of the sub-machine gun menacing all, the leader smashed a huge display counter with a single blow of a pistol butt. He gathered up piles of sparkling stones, diamonds, rubies, emeralds, sapphires — and dumped them into a canvas sack. His eyes behind the black mask held wolfish greed. His hands were tense as talons as he worked.

Jules Pierrot, owner-manager of the store, seeing a fortune vanishing before his eyes, ran from a back office. He was wringing his white hands, biting his lip, his small, immaculately dressed figure bobbing along. Consternation twisted his pink-and-white face with its carefully waxed mustache.

“Stop! Stop!” he screamed, “Help! Police!” In a frenzy that was almost hysterical he flung himself toward the man who was pilfering the trays.

The machine gun instantly clattered with a ruthless, measured note. Its snout quivered like the black, evil head of a snake lashing itself in fury.

Bullets slapped and slashed against the spotless vest of Jules Pierrot. He gasped, screamed piercingly, and flopped to the floor in a thrashing, grotesque heap. Crimson oozed from his clothing sogging it down. Crimson dribbled from his open, gasping mouth. The bandit leader at the counter calmly ignored the horrible squirming of the dying man. Jules Pierrot kicked pitifully, then lay very still.

Another of the gang came in from outside. The clerks, frozen with fear at the sight of their employer murdered before their eyes, obeyed meekly when they were ordered to open the safe. Some of the shop’s most treasured possessions were stored in this. Every flashing stone and bit of gold was scooped into the bandit’s pockets or the canvas sack of the leader. Systematically, surely, ruthlessly, the raid went on.

FIVE blocks away from the scene of the crime a small, compact coupé hurled furiously ahead. A man was hunched in it, his knuckles showing hard and white as they pressed the black rim of the wheel.

Under the instrument panel before him a hidden radio blared out police calls. The strident voice of the announcer gave the news of the Pierrot robbery in a numbered headquarters’ code.

“Cars seventeen and twenty-six,” it said. “Go to Forty-eight Vanderbilt Avenue. Number nineteen. Cars seventeen and twenty-six.”

The man at the coupé’s wheel wasn’t a detective or policeman. He had no official connection with any law-enforcing body in the land. Yet he knew what No. 19 meant. A store was being robbed. Another crime was being committed in a city already terrorized by the black wave of lawlessness that seemed to be engulfing it.

The coupé driven by the man corresponded to neither of the numbers that the police announcer had called. Yet the concealed short-wave radio beneath its instrument panel was as efficient as that in any official cruiser. The coupé itself was fifty per cent more efficient.

Its tonneau and chassis housed a collection of uniquely strange mechanisms. Sheathed armor plating of finest manganese steel was hidden beneath the enameled aluminum body, making it practically bulletproof. Small racks of tear gas bombs, and flares were slung underneath, ready to be released at the merest touch on hidden levers. A special, electric-field detector behind a sliding panel in the driver’s door made it possible for the owner to guide the car along a highway at night without lights, utilizing the presence of parallel telephone wires alone.

Sensitive audiophonic ears in the car’s roof could pick up sounds at great distances. These were only a few of the amazing devices that its inconspicuous exterior concealed. Outwardly commonplace, the car was as mysterious as its driver.

Behind the prosaic features of the man at the wheel was hidden an identity that the police of a dozen cities had speculated upon, an identity that the underworld feared and hated; yet knew nothing definite about — the identity of the man called Secret Agent “X”!

Scores of rumors had run rife about him. Plots, by the law and the lawless alike, had been laid to trap him. Dark schemes had been hatched to blot him out of existence, by means of poisons, knives and bullets. Yet he still remained alive, an active menace to evil-doers, one of the most daringly unique criminal investigators in all the world. He was a genius of disguise, a master of a thousand faces, a person pledged to ceaseless warfare against the destructive, disintegrating forces of crookdom.

The features showing now formed an elaborate disguise, as impenetrable as scores of others he had worn. Volatile plastic substances, overlaid above flesh-tinted pigment, followed the contours of his own face, yet changed it, so that even his own parents would not have known him. His hair was a carefully made toupee. His features were mediocre and inconspicuous.

Yet the odd burning light in his eyes seemed to hint at personal magnetism and great intellectual powers. Behind that disguised face a formidable brain seemed to be at work — and was. Agent “X” was on the trail of crime again, out to do battle with evil and match his wits against a mystery that was as sinister as it was deep.

The radio before him still sounded, calling the police cars. And, as his own coupé sped onward toward the scene of the crime, he suddenly saw one of them.

A green roadster shot out of a side street, roared into Vanderbilt Avenue. Agent “X” swung around on screaming tires and followed it. The police car’s siren was wailing. The men in it were hawk-faced, clean-cut, alert. A sawed-off shotgun was in the hands of one. They seemed ready to do their duty in an effort to save life and property, and beat off a gang of desperate bandits.

The shattered glass front of the jewelry store came into sight. Agent “X” pressed down on the brake pedal of his roadster and tensed. He saw the black bandit car, saw the men with guns standing outside the shop, saw the heap of shattered window glass and the raided display racks. But he was watching the two cops as closely as he was the bandits.

And, as he looked, a strange, seemingly inexplicable thing occurred. One of the killers on the sidewalk turned and saw the approaching police cruiser. He spoke sharply to a companion. The man he had addressed yanked a small pistol from his belt, aiming not at the oncoming car, but straight into the air. His hand jerked. Something shot from the pistol’s muzzle.

THERE was a streak in space, a sudden, brilliant flash of green light. A fiery ball like a Roman candle hovered for a moment in the air. It drifted earthward, went out slowly, sparks issuing from it, and two more balls of fire from the pistol’s muzzle followed it. These were a bright, livid crimson, like some devil’s eyes, disembodied and drifting weirdly through space.

The effect of the three flashes on the police car was instantaneous. Hardly slackening its speed, its siren still screeching madly, it swung around a corner, headed at right angles to the block where the robbery had taken place.

Tense, straining over his wheel, Agent “X” watched and listened. The cruiser’s siren, like a mournful banshee wail, was growing dimmer now. Increasing distance lessened its note. There could be no doubt about it — the cruiser had made a deliberate detour at sight of those red-and-green flashes. And Agent “X” had recognized the lights. An experienced airman, he knew a Very pistol when he saw one. It was a device used by flying men to signal their comrades night and day in the sky.

And it had been used as a signal now — a signal for the police not to meddle in what was going on. A signal for them to shy off from the scene of a murderous robbery. They were doing it, too — obeying, for some strange reason, a command from the underworld which they were officially pledged to fight.

Agent “X” could not understand it. Trained to probe the most difficult enigmas, here was a mystery so bizarre and forbidding that it was like a challenge hurled into his very face. If the police were bowing to signals from criminals, what chance did the law-abiding citizens of the city have? Was it graft that made them do it? That seemed unlikely, for “X” had had experience with most of the heads of the department. They were honest, determined men, enemies of his though they might be.

Something unbelievably sinister seemed to be in the wind. Some force, unknown to “X”, but hideously real, must have made those cruising cops yield to the signals of a criminal band. And it wasn’t the first time it had happened. Other cops in the past week had done the same thing — turned tail and run like rabbits when those mysterious green and red signals flashed. What uncanny power did the underworld wield? Even Agent “X” could not guess.

Their raid accomplished, the desperate men who had robbed Pierrot’s Jewelry Shop came out of the store and crossed the pavement. “X” stepped on the gas, racing the car forward again. One of the gang looked up and saw him coming. Once more the Very pistol flashed its green-and-red lights, but “X” paid no attention. He drove straight ahead.

Seeming to sense that here was no cop or detective who could be coerced; seeing a lone man driving a small, unofficial looking coupé, the bandits ran toward their own sedan. One of them stopped long enough to send a burst of bullets toward “X”. They punctured the aluminum shell, but stopped harmlessly against the manganese steel beneath. But a cobweb hole appeared in the non-shatterable windshield, and a chunk of lead whistled dangerously close to the Agent’s head. Still he came on, a fighting gleam in his eyes, hoping by direct action to find out who these men were and by what mysterious means they had cast a spell over the police.

THE gunman leaped into the sedan. Its door slammed shut. With a screech of gears and a pale feather of smoke from its exhaust it shot away from the curb. Agent “X” followed.

The car ahead seemed to have a super-powerful motor. Its pick-up was incredible. In that first minute it leaped away from the Agent. But his small coupé was devised for the highest speeds, also.

He touched a lever beside his hand. This connected the regular feed line with a special tank set close to the car’s gas filter. High-test fuel under pressure, containing a percentage of liquid hydrogen, newest of fueling agents, mixed with the gasoline supply. He pressed the accelerator. The small car seemed to hurl itself ahead.

It ate up the distance between itself and the other larger vehicle. A rear window slid up. Once again the black snout of a machine gun quivered and flamed. The gangsters were firing for “X’s” tires, not knowing that those innocent black rims had fine-meshed steel screening hidden under the pliable rubber. Bullets hit them but glanced off. The bandit aimed for the windshield again. And Agent “X” rocked the car from side to side with deft twists of the wheel, spoiling the killer’s aim.

Ten blocks were traversed. Police cars were conspicuous by their utter absence. The whole department seemed to be lying low. Not even a cop on patrol was in evidence. And then suddenly another large car turned into the street behind Agent “X”. He saw it in his rear-vision mirror, thought for a moment it was a squad car. Then he caught a glimpse of an ugly, bloated face hidden by a mask. His heart leaped. Here was evidence that the robbers were part of a large, organized band.

An instant later more proof came. As though in answer to some signal sent out, or as if acting on prearranged orders, a third car swung out of a side street ahead of him. It turned the corner slowly, but instantly put on speed. It was on his own side of the street. He would have to pass it parallelly, and from the open side windows a half dozen gun muzzles projected.

Here were killers regimented and organized to the highest possible efficiency. Here was a death car, waiting to riddle him with steel-jacketed lead. He wasn’t even sure that his armor plate would stand such a salvo at close range. Certainly the force of it would destroy his windshield and side windows, and, if a stray bullet didn’t lodge in his body, he would have only luck to thank.

But he couldn’t stop. The speedometer needle had touched eighty. His tires were making a humming screech on the pavement. His “souped-up” motor was roaring like a Niagara beneath its vibrating hood. To turn a corner or thrust brakes home now meant swift destruction — just as surely as the vehicle ahead stood for grim death. Yet the hands of Agent “X” were steady as rock as he raced forward to meet his fate.

Chapter II

A HUNDRED feet separated him from the car ahead. Fifty. Twenty-five. As the muzzles of the gangster submachine guns lifted to pour a deadly, withering, broadside fire into his speeding coupé, Agent “X” pressed back with his heel at a spot under the seat.

There was a faint click, a whir as a tiny, high-speed electric motor was set in motion. The piston of an air-pump moved with lightning rapidity inside a piece of mechanism as delicately constructed as a watch. A white chemical in solution was sprayed thickly into the interior of the coupé’s hot exhaust pipe. At the same moment Agent “X” shoved the cut-out open, leaving a vent directly behind the roaring engine.

Clouds of black, impenetrable vapor shot out from under his car, rising on all sides in a dense curtain.

His coupé was hidden as though a pall of soot had dropped upon it. Through the blackness, the thunderous reports of his unmuffled, “souped-up” engine made a din like a battery of guns going into action. The smoke screen enveloped the gangster car as well as his own, blinding them, preventing any accurate aim.

Agent “X” braked slowly and pulled to the left. There was danger of a sudden, terrible smash-up, if the gangster driver lost his head and made some panicky maneuver.

“X” shut off his engine suddenly, and, in the deathly silence which followed, as his car shot ahead under its own momentum, he heard the shrill scream of brakes as the gangster car was slowed.

He continued brake pressure himself, driving in utter darkness, with only the instrument board light and his sense of direction to guide him, and he saw the speedometer needle go steadily down.

When his tremendous momentum had been checked, when the car was barely creeping ahead, he swung still farther to the left, guiding the coupé expertly till the fat tires were brushing the curb. The sound ceased in a moment. Agent “X” swung the wheel at once, pulled his coupé into a side street, heading off at an angle from the route he had been following.

He pressed the button under the seat a second time, stopped the pump mechanism and closed the cut-out. Accelerating slowly, he drew out of the black smoke cloud. It had risen to the housetops now. Long, eerie arms of dark vapor, whipped by the wind, seemed a ghostly symbol of the black crime mystery he was battling.

He drove away from the gangsters. No use following them now. The car containing those who had robbed Pierrot’s shop would be blocks away. He had saved his life by a comparatively simple trick. The Agent had been ambushed by waiting cars before. He never allowed himself to be caught in the same situation twice. The black smoke cloud was his answer to a danger he had anticipated before it arrived.

The sirens of fire engines were screaming as he drove away from the spot where the smoke screen had been laid. He passed a red truck with men hanging to glittering brass-work, roaring toward the scene of his escape. Some one had turned in a double alarm, thinking the black vapor meant an explosion or a fire. The bells of other engines were clanging. Three fire companies were converging on the spot. None of them guessed that the small innocent-looking coupé they passed had been the cause of it all.

Agent “X” didn’t wait to observe the excitement and consternation his smoke screen had left in its wake. It had served its purpose.

He passed two patrolling policemen. They were far from the scene of the Pierrot robbery. Yet he noticed that their faces looked tense and uneasy. They did not stride along with the confident aplomb of their class. There was a furtive, almost apologetic manner about them. Something deeper than the fierce criticism with which the press of the city had been lashing the police department of late lay behind this. The law was falling down. The police seemed to be hiding their heads in the face of the worst crime wave the community had known for years. Murders, robberies, stick-ups, burglaries were occurring night and day. They had been increasing for the past week, and still the department appeared to be doing nothing to cope with the situation.

With a bleak, cold light in his eyes, Agent “X” went to a telephone booth and called a number not listed in any directory. He pitched his voice to a different key, spoke with a deceptive accent, and almost instantly an answer came over the wire.

“This is Bates talking. That you, boss?”

THE man at the other end of the wire had immediately recognized the voice Agent “X” had used. He was Harry Bates, head of an extraordinary detective organization Agent “X” had built up at great trouble and expense. Men and women of various types and from all walks of life were in it. All of them had been secretly investigated by Agent “X.” None of them knew that it was his influence and his money, acting through Bates, that held their staff together.

Bates himself had never to his knowledge seen the man he called “boss.” Instructions came by phone or radio, money for expenses by mail. The “boss” was only a voice to Bates, and he did not guess that the man he worked for was the mysterious, unknown Secret Agent “X.”

“X” talked quickly, hoarsely, now, with an edge of sharp command in his voice.

“Your report, Bates!”

“I’ve been the rounds, boss, like you asked me to. The mobs are lying low. My men are covering the phony spots, but they haven’t picked up anything. It looks like—”

“Are you watching Connie’s place and the Escabar over on Ninth Avenue?”

“No, boss, I didn’t know that they—”

“Post men there. Tell them to circulate and get friendly. Increase their expense accounts.”

“Yes, boss.”

“And if you learn anything, broadcast on the dot of every hour using wave-length M, code 26G. Be ready for possible radios from me.”

“Right, boss.”

Agent “X” hung up and called a second number. This was one listed as the Hobart Detective Agency. It was another of “X’s” subsidized organizations, working independently of Bates, having in fact no knowledge that Bates and his staff even existed. It was run by Jim Hobart, a former police detective, dismissed from the department on trumped-up graft charges, and befriended by “X”. The voice of the Agent changed again. It was more friendly now, yet still brisk, concise.

“Martin speaking. What news, Jim?”

“None yet, Mr. Martin. I can’t find out who is doing the dirty work. The big gangs are quiet. But there was a pay roll stick-up at Consolidated Wet Wash this noon. Eighteen grand grabbed! And this morning a gang of guys cleaned out the safe of the City Savings.”

“I know it,” snapped “X” impatiently. “What we must learn are facts — who’s behind the robberies, what crooks are operating, where the money’s going! How about the Shandley Hotel — are your men watching it?”

“Sorry, Mr. Martin. It’s one joint I didn’t think of keeping track of.”

“Why not? It’s a gamblers’ hangout. Somebody must be making money, and spending it — possibly at cards. The Shandley is a place you must watch. Send Bailey and his girl friend there with cash enough to crash a game if they get the chance.”

“Right, Mr. Martin, I’ll do that. You sure keep track of the hot spots.”

There was respect, admiration in Jim Hobart’s tone. Agent “X” chuckled softly as he hung up. Keeping track of the “hot spots” was part of his strange work. Yet Hobart knew him only as A. J. Martin, inquiring newspaper man. Hobart believed “Martin” worked for a large press syndicate; thought that Martin’s concern with crime was in the interest of inside stories for his sheets alone. And Hobart was a willing helper.

But without “X’s” supervision, without his vast knowledge of crime and criminals, without his awareness of the darkest, most secret dives of the underworld, neither Hobart nor Bates could get more than routine results. It was Agent “X,” Man of a Thousand Faces, uncanny genius of disguise, who moved them like pawns in his ceaseless game of death with the underworld.

He left the phone booth and stopped in passing at a branch post office where he had rented a box under the name of “F. Jones,” and where he occasionally received mail. He half expected a letter now, and he wasn’t disappointed. A blue envelope was waiting for him, addressed in small, clear writing and carrying a faint trace of feminine perfume. The Agent picked it up eagerly.

IN ALL the world there were only two people who knew the exact nature of his amazing, daring work. One was a man in Washington, D. C., a high official of the government, known to “X” as K9. The other was Betty Dale, blonde and lovely girl reporter on the Herald, whose father, a captain of police, had been slain by underworld bullets years ago.

Never had Betty seen the Agent’s real face; yet this strange, brilliant man of a thousand disguises had won a lasting place in her heart, and built up an emotion that was deeper than mere friendship.

The blue envelope was from Betty Dale. Yet it was no love letter. It was a report, brief and to the point, addressed simply to “Mr. Jones,” Box 29—a name and a number “X” had given to Betty if she ever wished to communicate with him.

“Dear Jones,” it said. “I have learned something that I can’t even reveal to the paper. Yet I thought you would want to know. I saw an old friend on the force last night. He says that orders have come from higher up telling the police to lay off a certain criminal group now operating and showing signal lights to identify themselves. It isn’t graft. It’s something very powerful. I don’t know what. Please be careful.”

That last sentence was the only personal touch. It brought a smile to the Secret Agent’s lips. It was proof that Betty was thinking of him not only as a grim investigator — but also as a man, and a beloved friend. Betty, because her father had been in the department, had always been a pet of the police. As a child she had played around the precinct stations. She knew half the cops and detectives in the city by name.

She had been granted interviews with police heads when all other representatives of the press had been excluded. And now she had hastened to inform “X” of the sinister information she had picked up.

Yet it was only more confirmation of what “X” already knew. The police were steering clear of the band that displayed the red-and-green lights. A powerful force for evil lay behind those signals. A sense of menace, almost of catastrophe was in the air. Yet both were shrouded in black mystery.

Agent “X” destroyed the note quickly. It was unsigned, but there was danger that even its handwriting might be traced. There had been times in the past when the black shadow of the underworld had fallen on Betty Dale in a hideous reality. This must not be one of them.

The Agent’s lips were unsmiling now. He was troubled. His own operatives, working even under his directions, had failed to ferret out the identity of the signal-using gang. The city’s well-known mobs were apparently not active in the present crime wave. It was for him, then, to go straight to the heart of the matter himself.

Chapter III

IN ONE of his secret hideouts, Agent “X” removed the disguise he had worn in his deathly conflict with the bandits. For a moment he appeared as he really was, as not even his closest associates had ever seen him. And the face exposed under the light above his triple-sided make-up mirror was almost as remarkable as the man himself. It expressed character, versatility, mature strength and youthfulness — according to the angle from which it was viewed.

The features were even, the lips firm, the forehead high and wide. From below, the fighting, stubborn chin was most prominent. Looked at from directly in front, the Agent’s uncannily intense eyes seemed to eclipse all else. At an oblique angle the faint lines and bunched muscles on his smooth face appeared to be the indelible records of all the strange, harrowing experiences through which he had passed.

He hunched forward now. His long strong fingers reached out. From his materials he selected those he needed, and, from a series of photographs spread out beside him, he proceeded to build up another personality.

The photographs were of himself. They did not depict his real face, but one that he had worn often before — one that was well known in many sections of the city. They were photos of a man called Elisha Pond, depositor in one of the city’s greatest banks, member and frequenter of the town’s most exclusive clubs, a man seemingly of age, dignity, and solid respectability. No one would have believed for an instant that he and the notorious Agent “X” were one. Pond was put down as a person of important affairs, a director in many companies.

Just how important his affairs were, his acquaintances did not guess. But it was under the name of Elisha Pond that Agent “X” drew out the money necessary to carry on his campaign against crime. It was under that name that he held a fund, subscribed for his especial use, and supervised by one man only, the mysterious K9 in Washington.

When his disguise was complete, that of a strong, quiet-faced, gray-haired man, Agent “X” dressed carefully. Pond, as an individual of means and importance, must always live up to his station.

In the secret pockets of the suit that “X” put on, however, he slipped the many strange devices that he was in the habit of carrying.

When all was ready, he went quickly into the street, using a back exit of the hideout. He walked rapidly several blocks, summoned a taxi and rode to one of the city’s best-known hotels.

From the lobby of this he called a wealthy, exclusive institution. This was the famous Bankers’ Club, of which Elisha Pond was a member. He asked to speak to Jonathan Jewett, the hard-headed president of the Northern Continent Insurance Co. “X” knew Jewett’s ways. Jewett always stopped at the club after work for a cocktail and a chat. The Agent knew furthermore, that Jewett had suffered indirectly at the hands of the gangsters now terrorizing the city.

An affiliate of Jewett’s company, handling fidelity, liability and burglary insurance, had been asked to meet policy payments a dozen times in the past week. That meant thousands of dollars loss to the affiliated concern. Jewett should be in a fit mood to be used as a pawn in a plan the Agent’s cunning brain had devised. That plan was the formation of a committee to cross-question Police Commissioner Foster.

“X” suggested that Jewett select certain men for the task. With quiet persuasion he stirred the insurance man’s emotions, playing on his indignation over the money lost, getting Jewett to agree to his proposal to have Foster, a club member, come down and be put on the mat. It was Jewett himself, however, who suggested that Pond be one of the committee-men. This had been part of the Agent’s own plan from the beginning. But he had cleverly let it appear as though it were Jewett’s idea.

When he sped to the Bankers’ Club just before six, the commissioner was already there. Foster looked harried, worried, and was pacing a private rear room tensely. Jewett, tall, menacing, indignant, because of the money his enterprises stood to lose, was glaring at him. Jason Coates, a small, sharp-featured man, who had run unsuccessfully against the present mayor, and hated him and his commissioners, was sneering openly at Foster.

John Harrigan, a financier with large holdings in munitions, was another member of the committee. Christy, a bland-faced broker, was still another.

Foster stared straight ahead of him, meeting no one’s eyes directly. A limp rag of a cigar, chewed beyond all appearance of a smoke, hung from his lips.

HARRIGAN was endeavoring to be diplomatic, trying to calm Foster’s evident irritation at this move his club members had made. For Harrigan was a friend of the mayor’s, a staunch supporter of the present administration, and had been dragged on the committee against his will.

But Foster seemed to feel himself attacked from all quarters. He brushed Harrigan’s diplomatic, pleasantries aside. He shot a venomous glance at Jason Coates, then spoke hoarsely, bluntly answering the criticisms that were hurled at him.

“I refuse to admit the charge that my department is inefficient,” he snapped. “I’ve ordered the men under me to do everything in their power. They are doing it, gentlemen. That is all I have to say.”

His face whitened as he said this. Agent “X,” watching closely, saw that the man was lying. “X” had seen many men lie. The expression on Commissioner Foster’s face, the telltale wavering of his eyes, only deepened the Agent’s belief that something strange and sinister was wrong with the working of the city administration.

A dead silence followed Foster’s speech. In the period that it lasted, the shrill cries of newsboys floated up from the street through an open window.

“Extra! Read all about the big robbery. Storekeeper murdered! Five hundred thousand dollars in diamonds stolen!”

The sound was like fresh fuel heaped on a smoldering fire. Jonathan Jewett struck the table with his fist.

“The citizens of this city will demand a reckoning!” he cried. “You’ll find yourself out of a job, Foster!”

Commissioner Foster, holding himself stiffly, stared not at Jewett, but over his left shoulder into empty space — as though he were seeing some hideous specter. He licked quivering lips. His face twitched.

“There’s nothing more to be said, gentlemen! If you don’t like the way this city’s being run — go to the mayor. Perhaps he’ll give you satisfaction.”

He strode forward hurriedly, jerked open the door and slammed it after him. His quick steps could be heard receding, mingling with the persistent cries of the newsboys still outside, advertising the news of the latest criminal outrage.

Jewett turned on his companions bitterly. His face was screwed into knots of anger. He clenched his fist again. “We’ll take him up on that! We’ll see the mayor and ask that a change of personnel be made in the police department. If he won’t listen, I’ll use my influence to see that the city loan he’s asking for doesn’t go over.”

Harrigan looked troubled. “I doubt if you can see his honor,” he said. “I happen to know that Mayor Ballantine is a guest on board Monte Sutton’s yacht, the Osprey.”

Jason Coates, political rival of the mayor, nodded and sneered. “I read about that! He’s going for a cruise to Southern waters for his health. He’s going to run away just when he’s most needed.”

“But he’s changed his plans,” said Harrigan hastily. “The cruise has been postponed indefinitely — till city affairs smooth out. His visit to the Osprey tonight is a purely social one.”

“We’ll see what he has to say anyhow!” growled Jewett.

The five of them, in Jewett’s private limousine, drove off into the winter night. Harrigan, worried and silent in the face of Jewett’s anger, directed the chauffeur. The Osprey was close to one of the city’s most exclusive residential sections, at anchor in the river near a swanky yacht club.

Jewett arranged for a speed boat to take them out. Bundled in their heavy overcoats, they raced across the dark water, sweeping up to the yacht’s companionway.

A score of prosperous looking men and women in evening clothes were sitting in the big saloon. Several couples were dancing on a small polished floor that had been laid in its center. A jazz orchestra, on a raised platform under the shaded lights, sobbed out a melody. Cocktail glasses were clinking. Light conversation and laughter sounded above the music. Monte Sutton’s guests were obviously enjoying themselves.

Then “X” saw Ballantine. The mayor’s appearance was in sharp contrast to the others. His stocky, broad-shouldered figure was slouched dejectedly. There was a grayish hue on his pouchy face. Wrinkles of worry creased his eyes. His lips were clamped over a cigar. He was solemn, distracted, staring ahead unseeingly, rolling his large shoulders from side to side like a restless bear.

JONATHAN Jewett made straight for him, with Harrigan, the munitions man, running a little ahead, to warn the mayor he had visitors. Ballantine gave a start and looked up uneasily. A combative expression appeared on his face. Harrigan took it upon himself to explain.

“These fellow clubmen of mine have come to make a few complaints,” he said. “I told them it wasn’t an opportune time; but they insisted. Mr. Jewett, it seems, has an ax to grind.”

“You’re right, I have,” growled Jonathan Jewett. “We saw your commissioner of police a few moments ago, Ballantine. We protested about the inefficiency of his department — and got no satisfaction. Now we’ve come to make some suggestions. Crime has risen fifty per cent in this city, and—”

Some of the guests were drawing nearer, attracted by Jewett’s loud voice. The mayor shook his head distractedly.

“Not here — please! If you want to talk let’s go somewhere where we can be alone.”

“That suits me,” said Jewett.

Monte Sutton, owner of the Osprey and the mayor’s host, was courteous and diplomatic. With a slightly bored expression on his handsome face, he led them to a small writing room.

“You won’t be intruded upon here, gentlemen,” he said. “Now get the poison out of your systems.”

Coates began to make sneering comments on the general inefficiency of the administration, hinting broadly at graft, predicting that the voters would cast their ballots differently in the next election. Jewett thundered about the rising tide of crime. Harrigan tried to steer conversation into more peaceful channels, and Agent “X,” in the role of Pond, stood quietly by, watching and listening.

That the mayor was worried was obvious. There were gray shadows under his eyes. He threw out his hands, and snapped up his head as questions and criticisms were shouted at him.

“Am I to listen to every faultfinder who cares to speak?” he said. “Am I to alter my policies to suit any committee of citizenry that comes along?”

Jonathan Jewett thrust the evening paper forward, with its screaming headlines. “I don’t give a damn about your policies, Ballantine! But this crime wave has got to stop. I’ve spoken to your police commissioner — and he gave me no satisfaction. If you don’t bear down on him yourself, and see about a shake-up at once, I’ll use my influence to hinder your administration in any way I can. You might as well know that now!”

The mayor faced his critic. His voice was low, hoarse. “There are factors at work that none of you know anything about,” he said. “I’m running this city with the good of all in mind. I’m satisfied that the police are doing the best they can under the circumstances. Commissioner Foster is answerable to me alone — and I find no cause for dissatisfaction in the way he is carrying out his duties.”

A stunned silence met this retort. Then Coates gave a harshly sneering laugh. Jonathan Jewett spoke furiously:

“You don’t think a police shakedown is necessary then? You are satisfied to let the criminals of this city plunder and murder as they will? You don’t want to protect the lives and property of honest citizens? By gad, Ballantine, it would seem almost that you have told the police not to interfere!”

A trembling that was very much like some mysterious, deep-seated terror shook the mayor’s body. He clenched and unclenched his hands, swayed his form from side to side.

“I–I refuse to talk any more!” he said wildly.

Chapter IV

THAT he meant what he said was evident. The fear that tensed his body seemed to have sealed his lips.

Harrigan was the only one of the group invited by Sutton to remain on the yacht. But he declined, saying he had an appointment ashore.

The committee from the Bankers’ Club left as it had come. The members of it formed a silent group as they crossed the black water in the speed boat. Each was preoccupied with his own somber thoughts. But the Secret Agent was the somberest of all.

“X” left the others when the speed boat landed. He refused Jason Coates’s invitation to return to the club and discuss politics, turned down Jewett’s offer to give him a lift in his car. He gave as an excuse that he had pressing business in the neighborhood. And how pressing that business was, none of them knew…

Much later that night, when the streets were quiet, Agent “X” appeared again. But no one would have recognized him now as the wealthy, dignified Elisha Pond. He was clad in faded blue trousers. Dusty shoes with thick rubber soles were on his feet. A turtle-necked sweater was pulled up to his chin. A cloth cap half covered his face. His features were disguised again, ugly and shapeless now. His brows were heavy, and a black substance that gave the impression of a stubble of beard was pressed into the plastic material forming his face.

He was impersonating a night prowler, a burglar or sneak thief, and under his arm was a worn leather kit containing a set of regulation burglar tools. But these were for appearance’s sake only, to be left behind as misleading evidence in case he was chased by the police. His own set of tools, made of the finest chromium steel, and unrivaled by those of any burglar in existence, were the ones that would do the strange work he had in mind.

Furtively, using the darkest streets he could find and imitating the actions of a night-marauding thief, he made his way across town. Several times he passed patrolling police. But they didn’t see him, so careful was he to keep in the shadows and so soundless were his rubber-soled shoes. But he noticed them — noticed that even these cops on the beat seemed afflicted with some emotional malady.

For they looked uneasy, nervous. They were confused and strained by orders from headquarters probably — orders which were inconsistent with the duties to which they were pledged. He didn’t doubt that they, too, had been instructed to steer clear of any mob showing the mysterious red-and-green signals of a Very pistol.

Agent “X” felt sorry for these men. They must believe secretly that the department they had served loyally for years was going to pieces. They must think corruption had eaten into the lives and minds of the men over them.

It was close to midnight when at last he reached a peaceful, old residential avenue. Prosperous homes lined it. Leafless trees stood in long, even rows.

The Agent walked several times along the block on this street, staring sharply at a certain house, a two-story brick residence, carefully cared for like the others. It was the Ballantine mansion, where the mayor had lived through all his rising political years, and where he still lived, as the city’s chief executive. There was a spacious lawn around it, and a sizable backyard.

Silently Agent” “X” climbed a picket fence and stepped onto the lawn. Wraithlike he moved across it, toward a big bay window at the side of the house. His actions were sure, calculated. Once, in another disguise on a different case, he had interviewed Ballantine in the role of a newspaperman. He remembered the mayor’s large study, recalled the big safe where Ballantine kept his private and semi-official documents. Surely, here if anywhere, would be a clue to the thing Agent “X” sought.

He went to the big bay window, skirted it and came to an outer door. This was a side entrance to the house, the door used by the mayor in summertime to come out on his lawn and chat with his neighbors over the fence.

With one of his chromium master keys in his hand, Agent “X” came close. There were no lights showing in the house. If the mayor or any of his family were home, they had long since gone to bed. Perhaps Ballantine was spending the night on Monte Sutton’s yacht again. In any case, Agent “X” knew how to enter quietly.

BUT at the door he paused. The Fates seemed trying to aid him. The door was not shut, nor even locked. It was open about six inches, and when he looked carefully, he saw something — a man’s soft hat — wedged in it to keep it from making any noise in the night breeze.

“X” slowly replaced the chromium tool in his pocket. No use for that now. Here was a strange turn of events. He had come to enter the house only to find that it wasn’t necessary. The place was already open.

“X” moved the door slowly, careful to avoid any faint squeak of the hinges. He stepped across the threshold into a hallway, closed the door after him, wedging it as it had been. He moved straight ahead, a flashlight in his left hand ready for instant use, his gas pistol in the other, and every faculty alert.

He had not been in this hall before, but he could guess at his surroundings. The first door at his left would be that of the study, the chamber in which he planned to go. He reached this and found that it was open, too. Then, as he paused and listened, he heard a faint sound inside, a soft, eerie rustling.

Slowly he shoved the door back, and looked into the room. In a far corner where the safe was located a faint light showed, the glow of an electric torch with a paper cylinder over its end to direct its rays in one direction only. This was making a glowing spot on the floor close to the safe. In this tiny arena of light, a man’s hands were moving white papers, shifting them and examining them with quick fingers.

He was so intent on his work, so eager, that he had no inkling of Agent “X’s” presence. “X” couldn’t see his face at first, not until his own eyes became used to the bright spot of light and things around its edge became faintly discernible. Then he started.

His eyes narrowed. He bent forward tensely. For the features of the man before him were familiar. He had spoken with this man a few hours previously. The silent, absorbed figure raiding the mayor’s safe in the dark of the night was Harrigan, distinguished member of the Bankers’ Club, and enthusiastic investor in munitions.

Chapter V

FOR tense seconds Agent “X” studied Harrigan’s face and movements. He was the last man “X” had expected to find here. Yet a possible explanation immediately suggested itself. Harrigan had been on the club committee which went to the yacht to cross-examine the mayor. He had acted as peacemaker, he was a loyal supporter of the party to which the mayor belonged. But it was possible he had grown impatient at the way Ballantine and his commissioners were running the city. It was possible that he, too, had come here tonight in the hopes of finding some evidence which would throw light on Ballantine’s strange actions.

Agent “X” watched hawk-eyed. Harrigan was making a systematic examination of the documents the safe contained, piling those he had already looked at on one side, reaching for others at his left.

Agent “X,” in his rubber-soled shoes, walking catlike, slowly crossed the floor, till he stood directly back of the kneeling man. He could see over Harrigan’s shoulder now, read as plainly as Harrigan himself what documents these were. Most of them were uninteresting; copies of bills submitted to the aldermen, papers dealing with franchises, charters and the like.

Five minutes passed, and a faint noise came from somewhere in the house, as though a restless sleeper had stirred. Harrigan tensed. For a moment it seemed he might get up and go to the door. His hand hovered over his light. But the sound was not repeated. Harrigan went back to his furtive work.

It was then that Agent “X,” looking down, saw the paper which Harrigan drew from a black envelope almost at the bottom of the pile. Harrigan opened it like the others. His eyes started to scan the words. But Agent “X,” reading faster than the man before him, had already seen a sentence that held hideous meaning. Before Harrigan had gotten beyond the first paragraph, Secret Agent “X” spoke sibilantly.

“Keep quiet, and raise your mitts, guy!”

At the same instant “X” pressed the muzzle of his gas gun against Harrigan’s neck. The man before him let out one whispering gasp. The document fluttered from shaking fingers. His body became as rigid as though he had been turned into a frozen statue.

A second passed. The Agent spoke again. “Get up, mister. No funny business — or I’ll pull the trigger of this gat.”

“X” turned on his own flash, directing the beam into Harrigan’s face. The man’s skin had turned putty colored with fear. Caught in such a compromising position, surprised when he thought he was all alone, he was trembling with fright. “X” talked slowly, playing the role of a common criminal, to put Harrigan off the track.

“It seems like I’ve seen your mug somewhere before,” the Agent said. “Ain’t you one of the mayor’s pals? Tryin’ to double-cross the big shot, eh?” He gave a harsh chuckle. “Thought you’d make a little dough for yourself by blackmail maybe. It’s a good racket, guy, but you ain’t got the guts for it — you white-livered dude.”

“I’m not — I—Who are you?”

“Never mind. Stand over there by the wall. Keep your mitts up and your mouth shut. I got a little business in that safe myself. I brought my tools, but I see I won’t need ’em.”

Agent “X” turned his own flash on Harrigan, saw that the man was obeying orders, standing still, too frightened to do anything else. He put his burglar kit down with a slight deliberate clink so that Harrigan would notice it. He bent forward so that Harrigan might get a look at his disguised features. He made a pretense of going through a compartment of the safe. His other hand was gathering up the paper he had seen in Harrigan’s fingers. This he slipped in his pocket, eyes gleaming, and searched hastily to see if there were any others.

At that moment a distinct noise sounded somewhere in the house. Boards creaked above his head. Slippered feet scuffed. Some one had waked and was coming downstairs to investigate. With a sweep of his hand Agent “X” scattered the papers over the floor. He turned, snarled at Harrigan.

“You lily-fingered dub! You’ve muffed the job — waked the family. Now I gotta lam before they put the finger on me. Stay there till I get out. Don’t squawk, or I’ll drill you.”

His face screwed into the vicious lines of some underworld night prowler, waving his gun at Harrigan, Agent “X” backed toward the doorway and went out. In a moment he was on the dark lawn.

THERE were lights in the upper part of the house now. Some restless sleeper had been disturbed. But “X” knew that Harrigan had time to make his getaway. He knew the man would take no chances of being found in a position which would ruin his reputation and cause a city-wide scandal. He didn’t wait to see Harrigan come out. He could set one of Hobart’s men or Bates’ to shadow Harrigan if necessary, and see if his purpose in coming to the mayor’s study was the one “X” had figured out.

Harrigan didn’t interest him at the moment. It was the paper out of Ballantine’s safe which made his heart leap. Blocks away from the mayor’s house, in the shadows back of an empty store, Agent “X” drew the paper from his pocket and turned his flash on it.

As he scanned the words carefully, his blood seemed to run cold. Here was the answer to the black mystery he had been investigating for the past thirty-six hours. Here was a criminal document containing a message so terrible that even his own fertile imagination hadn’t conceived of such a thing. It was typewritten on plain bond paper. It said:

The calm, fearful purport of the paper shocked “X”. He had dealt with scores of criminals. He had ferreted out crimes, blocked vicious onslaughts of the underworld on law-abiding citizens. But never had he run across a scheme as cold-bloodedly ruthless as this. The lives of thousands, perhaps millions, of unsuspecting innocents had been put in jeopardy that a human monster might enrich himself.

Like terrible, slumbering germs of Death, those bombs lay somewhere among the labyrinthine streets of the city. Like germs that would at an instant’s notice grow into a blight of red carnage unparalleled in the country’s history.

“X” HAD a vision of great buildings falling down with terrible impact of tons of steel and stone smashing down to break and rend bodies, crush out human lives, kill and maim. Men, women, and little children would be the victims. If what the Terror said was true, no earthquake or giant tornado would leave behind it a more appalling tide of death and desolation.

For a moment emotion choked in the throat of the Agent “X.” For a moment a passion of loathing such as he had seldom felt in his career held him in its grip. He was conscious of trembling; conscious of standing there in the darkness with his clenched fists and staring eyes. He had an impulse to go to the nearest great radio broadcasting station and send out a warning to the city’s population. If they understood their danger, there would be a general exodus of citizens. They would run fear-stricken from their homes, even leaving their possessions behind to get away from the unseen menace.

But, even as the impulse came, he knew that those who heard would not believe. A few might. Others would be uneasy, but too sluggish to run. Still others, the great majority, would laugh, and say this was only the story of some wild-eyed madman. Nothing so fantastically horrible could exist surely, they would think.

Yet, “X” remembered having read a notice of the squatters being removed from Baldwin Island. The press had kicked up a furor about it. It was an example, they said, of municipal callousness. Without a definite reason, without giving them time to make other plans, the city had swept down and forced the squatters from their shacks. Many with families had protested loudly. Charitable souls had come forward to help them. But there were some among the squatters who stated defiantly that they would not be driven from the only homes they knew. They said they would go back.

And tonight was the 15th! What if some of them had sneaked back? They had no inkling of why they had been driven away. What if a few of the pitiful human derelicts, struggling to keep soul and body together, victims of the great depression, had returned secretly to their homemade shacks? The rest of the world might regard these huts as mere loathsome heaps of old boards, tin cans and stones — eyesores on the landscape. But to those who had built them piecemeal, through long days of toil, they were homes.

Yes, tonight was the 15th, and in a little over an hour the Terror would make good his threat, or fail. If he succeeded, any squatters who had returned to Baldwin Island would be blown into shattered, bloody fragments.

This possibly alone was enough to send Agent “X” out on a mission of mercy. A benefactor as well as an avenger, he could not stand by and see innocent men destroyed.

There was a chance, too, that in a quick energetic survey of the island, with his experience behind him, he might find some clue to those who worked for the Terror. He might even locate the hideous bomb, or find tracks of those who had set it. If there were no squatters remaining, if he could not locate the bomb, then he would be a witness to its detonation — and see if the Terror had been correct in claiming NP as the world’s most terrible explosive.

“X” did not make a complete change of disguise. He stopped at one of his hideouts, doctored up his face slightly, then spent a few moments setting in operation an electrical mechanism that was housed in a cabinet standing on a table. When he left it, cogs were turning inside, and a thin, musical whirring came from the cabinet. Agent “X” went into the street and walked quickly to a garage where he kept one of several cars.

In this he sped to an old deserted dock on the river’s edge. Its piling was rotting away. It had been declared unsafe for use. Its owner had preferred to close it rather than renovate it.

Agent “X” slipped quietly through a high fence which closed off the end of the dock. He walked out on it, stopped suddenly and lifted a loose board.

A black, cavernous opening appeared. He stepped into this, descended a short ladder, and moved ahead on parallel boarding just above the water level. Walking forward and flashing his light, he came to a spot where a small, swift speed boat was moored.

It rested in a cradle of jute-lined bumpers that prevented it from scraping and squeaking. He stepped into the craft, started the muffled engine, and jockeyed out from under the dock’s forward end.

In a moment, the boat was a dark streak in the water, showing no lights, with only a white, ghostly plume of exhaust smoke at its stern.

Chapter VI

SEVERAL times, on his way, Agent “X” avoided police patrol boats. The harbor seemed full of them tonight. Without lights and headed toward Baldwin Island, he knew he would be stopped and questioned if they could catch him. But when one patrol craft came too close, “X” twisted the wheel, stepped on the gas, and went careening across the oily night swells. The throbbing, sixteen-cylinder auto-type engine under the mahogany hood drove the craft along at a swifter pace than even the fast police patrol boats.

Baldwin Island came into sight at last, a low line of blackness against the faintly lighter horizon. There were other police craft here, circling off shore. Evidently they had been told to stay away at midnight. The mayor must have let slip some inkling of what might happen.

Agent “X” throttled his motor and drifted for a minute, until the nearest patrol boat moved away. Then he gave the engine fuel again, sped on a straight course toward the dark unsightly island.

It rose rapidly above his bow. He slowed the engine at last, twisted the wheel, and slid into a small gravelly beach. In a moment he was on shore, pulling the boat halfway up the beach to prevent the ebb tide from taking it.

Scudding clouds slid across the stars. A faint, wintry crescent of moon cast a cold light. Underneath it “X” got a glimpse of the island. It was a place of ash heaps, dumps, and small storage houses. The largest building on it was a city-owned incinerator. It wasn’t a sightly place. Over on the north side were the shacks of the squatter colony.

Agent “X” made toward these, and, when a low ridge had hidden him from the water, he flashed his pencil light. Every few feet he saw evidence that the mayor had made effort to locate the hidden bomb.

Gangs of men had been at work here. Excavations showed in many spots, with fresh earth turned up. Yet obviously the mayor’s workers had failed to find it. No doubt the suspense was largely responsible for the mayor’s seeming fright.

Agent “X” didn’t pause to search for clues now. He’d had dealings enough with criminal minds to know the horrible warped cunning with which they worked. And before he searched there were the squatters to think of.

He came to a slight incline, climbed it, and saw the squatters’ colony ahead. Then he stiffened. Not one light showed, but several faint pin-pricks of illumination in the gloom. Smoke curled up from one cracked and rusty stovepipe above a nearby shack. The more daring of the squatters had made good their boast, and returned.

Agent “X” broke into swift strides. It was eleven-fifteen already. There was no time to lose if he expected to get these poor misguided people away. His face was bleak. His eyes snapped grimly. Horror, dread expectancy, seemed to lurk in the night about him on this desolate, barren island, and there were human beings, huddled in the very shadow of possible destruction.

He reached the first shack, burst open the door. There came a low whine, a growl. Then a furry shape bounded toward him. But a quick word from the Agent, and the dog that was about to attack him, paused and stood uncertainly. Something about the tone of “X’s” voice and the burning, intent light in his eyes always had an effect on animals.

He looked beyond the dog, saw an old man rising from a box seat before a rusty can being used as a stove. Heat came from the bent sides of the can. The old man had been warming his frail hands above it.

“Hyer — wadda yer want?” he cried. “What’s the idea, bustin’ in on a fella like this?”

Agent “X” stared at the man silently for a moment. Then he spoke in a calm, friendly voice. “Just dropped in, mister, to see whether you’d cleared out, and to warn you if you hadn’t to hurry up.”

The old man’s face distorted bitterly. “A detective, eh? Get outta hyer, dang you! Sic ’em, Bill!”

The dog, hearing its master’s order, growled and bristled, but refused to attack Agent “X.” The old man cried shrilly at the animal, but Agent “X” stepped closer, smiling. He reached out and petted the dog, whose hackles instantly went down.

The animal wagged its absurd stump of a tail. It was a mongrel, with a dozen strains fighting in its puny, courageous body. The old man stared in wonder, gulped.

“I never seen Bill take to a stranger like that before,” he muttered. “He must have a lotta police dog in him and like dicks.”

“I’m no dick,” said “X,” “I didn’t come here because the law sent me. I came as a friend to warn you. Do you know why you’ve got to leave this island?”

“Can’t say as I do. Some damned red tape, I guess.”

“No — I wouldn’t call it that. The island’s going to be blown up — that’s why. There’s a bomb hidden out here somewhere.”

“A bomb — say!” Suspicion came into the old man’s eyes. “I wasn’t born yesterday, fella. You can’t pull a yarn like that on me!”

“X” spoke softly, tensely. “I wouldn’t lie to you, friend. You’d better believe me. It’s true. Even the cops are afraid to come out near this place. Quick — get away before it’s too late!”

THE Agent’s hands went to his pockets suddenly. He drew out a wallet, took from it a packet of bills.

“Here,” he said quickly. “Take these, friend. They’ll keep you and Bill for awhile. Then go to this address — and there’ll be a job waiting.”

He handed the old man a slip of paper with the name and address of Jim Hobart on it. He would make arrangements to have the old squatter put on his payroll.

“X” left the shack abruptly, saw the form of the old man and his dog hurrying away. “X” himself went on to three other shacks.

In each he found a human being, the stubborn rear guard of the squatter colony. Briefly, tensely, he told them what he had told the old man, gave them money, urged them to hurry. Seeing he was not a cop, impressed by the cash he handed out, they obeyed at once. Kindness had accomplished what threats and force could not.

One more light at the outer edge of the squatter colony attracted him. He walked toward it, came to within twenty feet of it. Then he paused suddenly. For the door was opening and two figures were coming out — a man and a girl.

It was the girl who held “X” transfixed. He stared as though doubting his own senses — stared, and his whole body tensed. For the girl was well-dressed, not like the tattered squatters he had visited, or like the young man at her side who seemed also to be a squatter. She wore a wool suit with a fur collar, a little cloche hat, and under its brim a twist of blonde hair showed.

Agent “X” would have known her figure and her walk anywhere. It was Betty Dale of the Herald; the blonde and lovely ally who was one of the few persons in all the world who knew about his daring work.

An icy chill seemed to clutch at the Agent’s heart. What was Betty doing on this island at this time of night? What was she doing in the very shadow of hideous death?

The Agent stepped back. He puckered up his lips, sent a whistle into the night. It was birdlike, musical, yet with an eerie, ventriloquistic note that made it difficult to locate its source. It was the whistle of Secret Agent “X,” his odd, inimitable trade-mark.

Betty Dale stopped immediately. She gave a little gasp of surprise and clutched the leather brief case she was carrying.

“Betty!” said the Agent. “Betty — over here!”

She turned then, said something to her tattered companion, moved away from him and came toward “X.” Her eyes were bright. There was a smile on her lips as she approached. In spite of his disguise, one she had never seen before, she came directly to him. He didn’t need to introduce himself. She had heard that whistle too many times ever to mistake it

“Why, what are you doing here?” she breathed. “Did you know I was around? Did you get my letter?” There was eagerness, happiness in her voice. Her eyes were aglow with a light brighter than mere friendship. There was a flush on her cheeks, not caused by the crispness of the December wind.

“Yes, Betty,” the Agent said. “I got your letter, but I didn’t know you were on the island till I saw you just now. Why are you here?”

BETTY DALE tapped her brief case with slim fingers. “These squatters,” she said, “have been treated miserably. I’m collecting facts for a feature article in next Sunday’s Herald. I can’t understand why the city, yelling about relief to the poor, should hound these people who are hurting no one. The editor of the Herald feels just the same. My article will burn the mayor and his friends up. It ought to arouse public opinion. I had to come at night so the police wouldn’t see me. Steve, over there, a chap who built one of those shacks, brought me out in his boat. I’m just leaving.”

Agent “X” listened to the simple explanation of why she had come voluntarily into the shadow of destruction. It was one of those strange, ironic twists of Fate which no one could anticipate. He spoke quickly, laying his hand on her arm.

“I see, Betty, but you won’t need those notes. The city will understand soon why those poor devils were ordered away. The island is going to be blown up!”

Betty Dale started, paled, and stood very still. Her voice, sounded faint. “Blown up — why? I thought—”

“It’s part of a criminal plot, Betty. Part of the thing you spoke of in your letter. I won’t explain it all now, but the mayor himself is a victim of it. His hand was forced.”

“When — when will this happen?” Betty asked.

“At midnight!”

“Midnight — that’s only a half hour off!”

“Exactly. And that’s why we must hurry.”

Betty came closer, spoke quickly. “There’s a young fellow in that shack back there — a friend of Steve’s. He refuses to leave. I got most of my notes from him. He’s told me how hard things have been. We must warn him, too!”

The Agent nodded. “Wait here a minute, Betty. Steve has a boat, you say. I’ll get him to take his friend off at once. Then you can come with me. We’ll stand off the island, and watch for the explosion together.”

Agent “X” swiftly approached Steve. The tattered young squatter peered at him sharply.

“Say, are you a friend of Miss Dale’s? I didn’t know she knew any mugs over in this dump! She’s a swell kid all right. She’s gonna write up in the paper how they treated us!”

“X” repeated briefly what he had told Betty, explained why Steve must leave and take his friend with him at once. The boy’s face went white. He pocketed the money “X” gave him dazedly, turned and ran to the shack of his friend, and Agent “X” returned to Betty’s side.

“Come,” he said. “I’d planned to look around, but there isn’t time now. We’d better leave right away.”

Betty Dale took his arm. Together they hurried across the ash heaps and piles of dirt toward the spot where he had drawn up his boat. But before they reached it, Betty suddenly stopped and pointed.

“Who are those men?” she asked.

“X” saw them at the same instant — two furtive, swift-moving figures, just appearing from behind an ash pile. He paused, drew Betty back, and abruptly tensed in his tracks. For a harsh voice sounded directly behind him, a voice that gave menacing command.

“Don’t move — either of you!” it said. “I got you covered — and I’d just as leave shoot as not.”

“X” OBEYED instantly. He heard shuffling footsteps close behind him, felt a gun against his back. Then the speaker raised his voice and spoke again. “Here’s the bird, boys, and a jane with him. Come on over.”

The two that Betty Dale had seen came up quickly. They had twisted, brutal faces. Guns were in their hands. The Agent’s pulses hammered. His skin felt cold. Left to himself he would have made some swift attack. But the guns were aimed at Betty Dale, also. He couldn’t risk a bullet that might snuff out her life.

“Listen,” he said harshly, “this is no time for a stick-up. There’s a bomb out here somewhere. This island’s going up at midnight.”

One of the men broke into a cackle of derisive mirth. “Wise guy, eh! You’re telling us! Bomb is right — and you and the dame will find out more about it in a minute.”

The cords in the Agent’s neck stood out. He crouched, made ready to leap. But the quick, brutal voice of the gangster stopped him.

“I don’t know who this jane is, but it looks like you like her. Any rough stuff and she gets rubbed out, see? Come on, boys! Put ’em where I told you.”

With a single frightened scream, Betty Date tried to break away, crying for “X” to follow. But one of the men caught her instantly. A second man pressed a gun against her back. “X” saw his trigger finger tense. He spoke quickly, hoarsely:

“Betty — don’t! They’ll kill you!”

Feeling a crushing weight of horror upon him, Agent “X” allowed himself to be led along. These men were spies of the Terror. He realized that, now. Their faces were grim. They, too, were hurrying, anxious to get away from this place. Their actions supported his belief that the Terror’s threat was no mere boast. A gun was against “X’s” back, also. He didn’t fear that, but he was handicapped, made utterly helpless by the knowledge that Betty would be shot down callously if he made a move to save her or himself.

The gangsters veered to the left suddenly, took a narrow, ash-strewn path, and led their prisoners with them. One of them flashed a light. A squat brick building showed ahead. It was part of an old incinerating plant, discarded by the city since the new one had been built. It was windowless, merely a brick storage shed, but it had a strong, metal-bound door. This was open.

The gangsters thrust Betty inside, then “X.” They gave the girl a shove which made “X” clench his teeth in fury. The next moment he, too, was forcibly hurled into the shed’s interior. The gangster with the guns menaced them an instant. One of them spoke.

“We don’t know who you are, guy, but we can make a guess! You seem to know too much. One of the hobos out here told us you’d warned him and the bunch to beat it — on account of a bomb. I guess you’d like to know where the bomb is — and I’m gonna tell you. It’s right here in this shed, see? And you and the jane are gonna have a chance to watch how it works. So long, sweethearts! We’ll be seein’ you in hell!”

Harsh laughter followed this sally. The door slammed shut. A padlock clicked in a staple outside. Then came the sound of footsteps receding.

Betty Dale and the Agent were prisoners, close to the bomb of death — scheduled to explode at the end of a mere twenty minutes.

Chapter VII

RIGID horror gripped the Agent for a second. He leaped to the spot where Betty Dale had been hurled to the floor and flashed on his light.

She was just getting up. Her voice sounded clear and steady beside him. “I’m afraid I got you in a jam,” she said.

The Agent gave a harsh laugh. “It’s the other way round, Betty! If I had gone on and left you alone — this wouldn’t have happened.”

He moved away, flashing his light quickly in all directions. Horror still held him, made his neck and hands feel cold. He wasn’t thinking of his own life, or of Betty Dale’s alone. He was thinking of those other thousands, millions perhaps, whose existences were threatened as long as this man, the Terror, was active — as long as the dozen bombs remained unfound.

His light paused abruptly, making a round spot at one end of the window-less chamber. A cluster of bricks had tumbled out here. A few broken pieces lay on the floor. Others had evidently been carted away. But what held “X’s” interest was a spot above the bricks, on the wall itself, which had apparently been cemented over. The work had been done cleverly, with dirt and soot rubbed in, blackened like the rest of the building’s interior. But the sharp eyes of Agent “X,” trained to observe minute details, saw instantly that it was only camouflage.

He strode forward, touched the sooty surface with a finger tip, and found hard, new cement beneath the grime. This job had been done within a few weeks. No other part of the building showed repairs. The significance of the thing was obvious. Betty Dale, watching him, understood too. She had followed, was close at his side, staring at the wall in uneasy fascination.

“They said the bomb was in here. That must be it — behind that plaster! Is there any way we can get it out — stop it?”

For answer “X” reached down and picked up a piece of brick. He tapped the cement gently; knew immediately by the sound that it was at least a foot thick, shook his head.

“If we had time, Betty, I could do it. But, there isn’t time!”

His light left the wall, returned to the heavy door. No lock showed on the inside. Its oak beams were reinforced with bolted strips-of metal. It would withstand at least an hour’s battering — and it was now nineteen minutes of twelve.

Every second counted. Death and time seemed to be working hand in hand against them. The girl sensed the hopelessness of their position, sensed that Agent “X” and she were doomed to die, yet the smile was still on her lips.

The Agent’s fingers gripped hers for a moment. He smiled into her eyes, then moved up to that door which seemed an impenetrable barrier. Looking at it now, briefly, speculatively, it was still the time element which baffled him. Given forty minutes, a half hour even, he was certain he could escape from here. The men who had shut Betty and himself inside this room of death did not know evidently with whom they were dealing. They had no knowledge of the strange, ingenious devices carried by Agent “X.” They did not guess the full extent of his resourcefulness.

“Hold the light, Betty,” he said suddenly. “Keep it on the door.”

Feverishly he took out his kit of tools. He scanned them for a moment, shook his head, laid them down. These bits of metal with their goose necks and queer pivotal extensions had served him well for a score of times. With them he had opened bank doors, picked locks that were considered invulnerable in his ceaseless quest for evidence of crime. But they would not serve him now — with only blank boarding to face.

He lifted one foot instead, reached inside his shot sole, and drew out a small implement concealed there. This, too, had performed seeming miracles in its time. At one side of it was a tiny, paper-thin hacksaw, on the back a file, made of a thin strip of black diamond, set in steel-hard cement.

The hinges of the door were fastened laterally, screwed inside the frame. Only their ends showed, and hinged joints themselves, with the metal pivots that held them together. These were welded in, with rounded heads top and bottom. Rust was flaked on them in mantling cakes.

Quickly, energetically, Agent “X” drew his diamond file across them. Under its keen teeth the rust came off. In a moment he had bared the bright metal of the pivot ends. But filing would be a long process. There wasn’t time for that.

Time — with that dreaded thing sealed in the wall close by. Time — with every second bringing them closer to eternity. Once the Agent glanced at Betty. A smile of hope, faith, was still on her lips. It clutched at his heart. The girl, who had seen him do the seemingly impossible before, trusted him now, thought that he had found a certain way out. Her hand was steady on the flash. Its beam gave “X” ample light to work by.

WITH tense fingers, he turned the file over, thrust the hacksaw blade against the line where the pivot head and hinge were joined. But rust still clogged the crack, hampered him. He ran and got a piece of brick, came back and knocked violently against the hinge.

Some of the rust came out. He struck the pivot up to give more room. Then, while the slow minute hand of his watch moved upward toward the spot which spelled destruction, he drew the hacksaw blade back and forth.

The sound of its teeth mounted. It snarled, bit into the metal. It rose to a thin wail, like the moan of a frightened animal there in that room of death. The Agent’s arm worked like a piston. His breath came in short, quick jerks.

The blade was halfway through now. Rust clogged it further as it bit in. Sweat stood out on the Agent’s forehead, though the chill of the December night lay like a pall within that room.

The hacksaw screamed more slowly. It rasped, lurched forward. One of the pivot heads dropped off. He did not attack the head at the other end. He stood erect, moved to the door’s top hinge now, thumping it first with the brick, then using the saw again. Once he stopped, asked a question.

“What time is it, Betty?” He tried to make his voice sound casual; tried to hide the eager, fearful note it held.

Betty glanced at her wristwatch. Words seemed to come from her throat with difficulty.

“Ten minutes to twelve,” she said. “Do you think—”

She didn’t finish. He didn’t answer. He went to work again, more quickly, more furiously than ever; drawing the saw across the pivot in thrusts that threatened to snap the blade; risking all in snarling, lashing strokes. Seconds seemed to be racing. His own pulse-beat seemed to mock him. Then the saw’s teeth slid through. The other pivot head came off.

He dropped the saw into his pocket, snatched up one of his small tools. It was a straight bit of steel like a nail set. In his other hand was a piece of brick.

Swiftly, surely, he hammered down on the tool’s top, struck the hinge pivot out of the joint. The tiny pieces of metal, which had held them prisoners like iron bars, dropped to the floor.

Agent “X” attacked the door. It fitted snugly. The padlock outside held one end. The wedged sections of the hinges held the other. He dropped to hands and knees, felt along the door’s bottom, and thrust his fingers in. Muscles along his back and shoulders rippled as he heaved. Betty had turned the flashlight down. There was no sound in the room, save the Agent’s labored breathing. Then the big door squeaked, stirred.

He drew the bottom toward him with a jerk that made the cords on his neck stand out. The wedged hinges came loose. The door broke away from its frame. The padlock staple prevented it from coming entirely free. But he cried out to Betty to step back. He caught the door’s edge, drew it inward — and a breath of chill night air came through the opening.

He seized Betty’s arm, pulled her from the building. “Quick, Betty! We must run! It’s our only chance. The boat!”

He didn’t know in which direction the nearest water lay. The prison shed seemed to be in the center of the island. It had no doubt been selected for that reason by the bomb planters, so that the Terror could make good his boast and destroy all. But “X” knew where he had left his speeding boat. His unerring sense of direction told him that.

He led the way, holding Betty’s arm. They raced across the ash-strewn ground under the bobbing beam of his flash. He knew it was a race with death, knew that now it must be five of twelve; knew that any instant, if there was a slip in time, a tiny discrepancy, the bomb might explode — and all his efforts would be futile.

Breathless, gasping, Agent “X” drew Betty along, till he saw the gleam of water ahead. Beyond it, far away, the twinkling lights of shore showed, and the lights of boats along the water’s surface. He turned a little to the left. There, by that mound of dirt hidden in the shadows, was where he had drawn up his own craft, the boat that would speed them away from this place of waiting death.

He almost lifted Betty from her feet as he guided her. Her breath was coming in quick gasps. Her fingers were clutching him, and suddenly “X” cried out.

“The boat — there it is!”

The slender shadow of the craft had caught his eyes. It lay where he had left it, drawn up on the sand. But even as he saw it and came close, a harsh, bitter exclamation was wrenched from his throat.

Betty stopping beside him, exclaimed, too. For the boat at her feet was not as he had left it. Some one, the men, no doubt, who had imprisoned them in the shed, had been at work.

Rocks lay in the padded interior. Skeleton ribs showed. The boat was useless, shattered beyond repair even if there were time — and, in the blackness behind them, in that prison shed, Death was crouched on its haunches like a black beast waiting to spring.

Chapter VIII

THE Agent turned on Betty Dale and uttered quick, hoarse words. “We must swim, Betty — swim at once!” Even as he spoke, he reached down, ripped open his shoe laces, drew off his shoes. Betty, following suit, kicked off her pumps and stood in stockinged feet.

The Agent’s eyes were bleak. He hadn’t told her the nature of that bomb; hadn’t said that if the Terror’s boast were true the very soil under their feet would disintegrate. There was distance between the shed and themselves now. Betty appeared confident. She was sure they were all right. But Agent “X” knew differently.

The girl was running like a slim nymph toward the cold December water. She flung her wool coat off, tossed her blonde hair back. The rigors of the chill water didn’t terrify her. Her young, strong muscles could cope with that. She waded in knee-deep, flung herself down. With long, clean strokes she swam ahead. And the Agent followed. He came close, whispered hoarsely in her ear.

“As fast as you can, Betty! Swim as you never have before! If you get tired — I’ll help you.”

Her expression showed that she didn’t understand his worry. She had proved her swimming ability often before.

“X” didn’t try to explain. No time for that now, and no use frightening Betty. The cold water leaped about their bodies. It clung with a chill that almost made their muscles numb. But their long, sweeping strokes held the cold at bay.

Betty turned her spray-wet face. “X” could see the dim oval of it in the starlight, see the clustering blonde curls low on her white neck. He knew that she was good for miles, using her even, racer’s stroke that had won her cups in women’s championship meets. His own muscles had been trained to endure endlessly. He could stay in the water for hours, swimming on his back if he became tired, floating if necessary. He was as much at home as a seal.

But the dread knowledge of what lay behind them hung like a lead weight around his neck. He stayed close to Betty, with a sense of waiting. There was no telling what minute the bomb might go off. Fast as they were swimming, he wasn’t satisfied. He spoke once again, something of the dread he felt in his voice.

“Keep it up, Betty — as fast as you can! Every stroke counts.”

They were two hundred feet offshore now. The Agent wished it were two hundred yards. He could almost sense each passing second. He was counting in his mind, keeping track of the minutes. It must be almost twelve! The arch criminal would make it a point to stick closely to his schedule. Midnight sharp would be the deadline.

Far off across the water he saw faint lights twinkling. People were there in their peaceful homes, all unknowing of the danger that lurked so close at hand. Nearer by were the moving lights of boats. Police craft, no doubt, and others going about their accustomed routine.

Then, on a hilltop somewhere on shore, he heard the solemn tones of a great clock booming the hour. The Agent tensed. It must be past midnight. Sound traveled at eleven hundred feet per second. And he heard the clock just striking now — which meant the hour was past — or else the clock was wrong. Surely the dread moment was almost at hand. He had struggled, worked, done his best for Betty and himself. Still they were under the black shadow of doom. Only three hundred feet separated them from the island’s shores — only three hundred feet of water beneath them and shuddering death.

HE came close to Betty, reached out a hand to her wet shoulder, felt the warm play of muscles beneath.

“Steady, Betty. I think—”

He did not finish the sentence. He heard the small, frightened cry that Betty gave. It stabbed at his heart. The Agent’s eyes recorded the hellish white-hot flash that erased the glow of the stars and seemed to sweep over their very heads. He saw the outline of the island, illumined now. But not the island he had moved on a minute before. The black bulk mushroomed out, spread like a menacing Titan across the blinding whiteness of the light.

And then his ears, receiving impression later than his eyes, heard a sound that was like thunder multiplied a thousandfold. It was a sound that had bulk and substance, a crushing weight of tumbling, fearful reverberations, almost shattering his eardrums.

Instinctively Betty’s arms wrapped around him. He held her small, tense body close to his. They were alone in a world of blinding light, of terrible sound, and of earth and rocks that rose volcano-like, seeming to reach to the very sky above.

He got one look at Betty’s startled, staring face. He saw her eyes grow big, her teeth set. He could not speak, could not make her hear. He could only hold her with his arm, trembling to think what thing would shortly follow.

For the three hundred feet that separated them from the island seemed pitifully small now. Fringing the black pandemonium of sky-tossed earth, a white line of water showed — like froth rimming the angry, cavernous mouth of some great sea beast. It rose higher and higher — salt water lashed to a foam by the concussion. It mounted, curled and raced toward them, in a roaring tidal wave.

Betty saw it, screamed once, in a surge of fear that she could not choke down. The Agent, seeing that wall of water, believed that it was the end. One thing alone stayed clearly in his mind. He must keep hold of Betty. If it were possible to survive he must not let that fearsome, onrushing fury snatch her from his arms. His hands locked around her. He kept afloat with the scissors strokes of his feet.

But in an instant even swimming seemed futile. For the water was almost to them, curling like a mountain top. There was a trough before it. They slid down into this, and as they did so, Agent “X” cried in Betty’s ear:

“Breathe, Betty! Hold it!”

He filled his own lungs till they ached. The water seemed to lift them in a mighty surge. They were borne up, up toward the foaming crest. Then the boiling spray engulfed them. Like straws they were rolled over and over; weighed down, hurled about in a Niagara of churning, fearsome water. More tumultuous than the roughest surf, more exhausting than anything “X” had ever known.

Once he felt a vibration in the water, a compression as though some great weight had struck, and a black something seemed to rocket close at hand. He knew it was a rock, falling from the island, and that the bulk of water above them was all that was saving them from the raining destructing of countless missiles. But his lungs were almost bursting. He feared for Betty. And so, still holding her to him, he struggled upward. It seemed that he would never reach the surface. The boiling foam had subsided now. He appeared to be in still black depths. He held Betty with one arm, pushed with the other, forcing himself toward the surface before it was too late.

Then his head came out. The rumbling roar of the explosion had ceased. The white light had gone, and his half-blinded eyes could not see the stars. But there was still movement all about them — and noise. The water was surging in a vast, sweeping tide. Stones were dropping on its surface in a pattering shower. Debris of all kind was falling.

Something hit “X’s” shoulder, made a stabbing pain. A rock splashed close by. Any instant death might come. Yet he dared not take Betty down into the depths again, and there was no assurance that a rock might not strike them under the surface as well as here.

He waited, paddling slowly in a solitude of blackness and death. And then a new menace came. For the tide had turned. He had lost all sense of direction, yet he could tell that in the last few seconds some change in the watery surge had come. The water that had gone out into the boiling wave was coming back, more sluggishly, to sink into the vast hole where the island had been, sink to replace tons of scattered earth. The Terror had fulfilled his threat, razed Baldwin Island to the water level. And now the waters were returning to cover the spot where it had been.

Agent “X” gasped as the tide seemed to reach for them. This was worse than any undertow. And somewhere ahead in the darkness, as the falling rocks began to diminish, he could hear the rushing, roaring sound of a giant whirlpool. It grew louder, closer every instant. He and Betty were being swept back toward it.

This was a new horror. They had lived through the tidal wave. But nothing could survive that sucking undertow. He knew it must be pulling debris down with it — as it would pull them, to crushing depths.

He fought now, snapped into action, brought all the power of his steel muscles into play. He turned over on his back, drew Betty on hers, placed his left arm under her chin, keeping her head up. It was a lifeguard’s maneuver, one that “X” had often used. It left his right arm free, the powerful scissors strokes of his legs unimpeded.

He swam as one would swim against a roaring current, swam with the blood pounding in his veins, with every muscle in his body straining like a tautened cord. Yet still the water bore him on. Still in his ears was that strange uncanny roaring. His eyes had grown used to the starlight again. He turned once, a tortured, straining face, and saw the boiling, deadly riptide where Baldwin Island had been. It was toward this he was going, toward the middle where horrors of green sea water were sliding down.

“Betty! Betty!” he called.

She stirred faintly then, as though the sound of his voice were bringing her back from great depths. But the moan that came from her lips ended in a choking gasp. She was on the borderland of consciousness, her lungs half-filled with water. He must fight it out alone, save her and himself, or go under with her to a watery death. The whirlpool could not last forever. The space the exploding island had made must at last fill up. The angry sea must reach its level again.

He fought with the frenzy of a man in the toils of some mighty beast. Yet the current drew him steadily closer. The white froth of the riptide was coming nearer. And Agent “X” almost gave up hope.

Chapter IX

HIS steely muscles could not exert themselves forever. His iron will could not battle endlessly against such overwhelming odds. Through seconds that seemed eternities he fought the sweeping, foaming current, till at last the tide, as though merciful to one who had struggled beyond all human endurance, began to slacken.

The Agent’s movements toward the snarling edge of the whirlpool slowed. He began to hold his own, began even to make headway against it. Behind him the sea lapsed into a low moaning whisper.

He was conscious of the water’s chill then, conscious of the black winter night around him. The cold cut into his very marrow as his own movements slowed. What must Betty Dale be feeling, still and limp in his arms?

He shook her gently. “Betty! Betty! We’re all right now.”

The faint sound she made frightened him. He turned her on her back, held her chin up, and moved her arms. She made another brief strangling noise. He saw then that he must get her out soon, drive the water from her lungs.

The thought that she was in danger clutched his heart in a grip of fear that all the terrors he had been through had failed to bring. He looked over the dark face of the water. Everywhere whistles were blowing and lights were springing up. Some were moving along the surface — boats.

Agent “X” filled his lungs with air. Not often did he ask anyone for help. Now it was not for himself, but for one who was more than a friend, one who had shared hideous dangers with him and had come through the Valley of Death at his side.

He gave a shout that sped across the water like a gull’s wild cry. Again and again he uttered it, till the wailing siren of a boat gave answer. He saw a light veer then, saw the red and green riding lanterns of a vessel coming fast.

He shouted once more, holding Betty’s small face up, moving her arms to drive the cold out. She couldn’t swim. She was almost strangled. Perhaps a blow from some passing bit of debris had struck her head. He trod water, keeping her afloat till the approaching craft raced nearer.

He could make out its lines now! It was one of the police patrol boats he’d seen earlier that evening, before the frightful explosion had come.

The blue-white beam of a spotlight whipped across the water, and Agent “X” waved his arm. The light centered upon him and Betty, and the boat swept close.

At the last it veered, then edged slowly toward them, drifting with the wind. Hands reached down from its low deck. Betty was taken aboard first and carried into the small warm cabin. “X” was helped from the water and followed.

Bluecoats stood all about them, men who, had they known “X’s” identity, would have snapped steel cuffs on him and menaced him with their guns. But they had no inkling that the mild-mannered stranger before them, in wet clothing, was the mysterious, uncanny Man of a Thousand Faces, regarded by the law as a desperate criminal. The Agent spoke quickly now:

“Get some blankets and liquor at once,” he said. “The girl must be attended to.”

A heavy-set cop bent over Betty to administer practical first aid, but Agent “X” thrust him aside. This was a job he would trust to no one. His amazing mind held data on many branches of science. Medicine was among those he had studied. He knew more tricks of resuscitation than any of these men around him.

He turned Betty face down on the floor, set to work expertly, moving her arms in a way that forced water from her lungs and started blood surging through her heart. In a moment she stirred and a faint trace of color crept to her cheeks.

Relief swept in upon the Agent now that he saw Betty Dale was safe. For a moment he allowed himself the luxury of forgetfulness, a second’s peace after the nightmarish horrors of the past half hour. But the cops’ grimly questioning faces brought him back to the sinister mystery of the explosion.

“The girl’s Miss Betty Dale of the Herald,” he said. “She went out to interview the squatters who slipped back after you fellows had driven them away. My name’s Ross. We were just leaving when the big noise came. What was it?”

The cops looked at each other quickly. In deliberately querying them first, “X” had checkmated questioning of himself. He kept up the pose of a puzzled witness of some mysterious happening.

“Did the city have dynamite on the island, or what the hell?”

“One guess is as good as another, buddy,” said a cop guardedly. “Maybe there was a powder house over on the dump. Who knows?”

Betty Dale was sitting up, talking with the police when “X” re-entered the cabin. They had delved into their emergency chest, provided her with an ill-fitting woman’s coat, dress, and a pair of shoes several sizes too large. She exchanged a single, meaning glance with the Agent.

“Please land me as soon as you can,” she told the cops. “I’ll want to turn in a story to my paper.”

The harbor patrolmen nodded. They seemed relieved when the boat finally edged into a small municipal dock.

CROWDS had gathered along the waterfront. Faces were tense with curiosity and apprehension. Questions were being asked in a dozen different tongues.

Betty and the Agent pushed through the buzzing throngs whose interest had been aroused by the mysterious explosion. These people didn’t know that the tall man in the wet clothing could have told them more about it than the police. They didn’t guess that the two before them had come together through the very jaws of Death.

Agent “X” summoned a taxi and took Betty back to her apartment to change her ill-fitting clothes. He cautioned her not to mention the men on the island or the fact that she had seen the location of the bomb. At the apartment door he said a hurried good-night and gave the cab driver another address. He stopped at last in the middle of a block, paid the taxi man off, and walked a hundred yards farther on. Here he went into the rear door of an empty house, the same hideout he had visited just before his trip to Baldwin Island.

Even before changing his wet clothing, he strode up to the odd apparatus that stood in a wooden cabinet on the table. It was a special type radio receiver. Simple as the thing appeared externally, it was a monument to the talent of Agent “X” in a field of science which many men made their life work. It represented hours of patient research, amazing inventiveness, and a deep knowledge of the principles of mechanics and radio engineering.

He called it a “radio wave camera,” and it was perhaps the only one of its kind in existence — a machine for taking permanent impressions of invisible radio waves. On a large revolving cylinder of white paper, operated by delicate clockwork mechanism, visual records of all the radio waves picked up within a given space of time were made.

The meter length of the great broadcasting stations showed here. Also calls corresponding to amateur stations, police cruisers, ships in the air and ships at sea.

More than five hundred tiny styluses, dipped in red ink and poised above the paper cylinder, were ever ready to descend and make their lines, as radio impulses operated electromagnets beneath them. All the broadcasts of the evening had made visual imprints. Each of those tiny, intermittent red lines corresponded to some orchestra, some speaker, singer or comedian in one of the big studios.

At other points on the white cylinder, code from ships at sea showed. The machine was extraordinarily apt at picking up this, the dots and dashes being plainly visible.

But Agent “X” at the moment was interested in none of these. He shut off the revolving mechanism, drew the cylinder from its drum, and ran his eye along a transverse blue line that had the figure twelve above it.

Twelve o’clock — the zero hour at which the awful bomb had been detonated! Had the Terror been lying? Was it an ordinary clockwork bomb, or had radio impulse really done the work?

The Secret Agent’s fingers trembled slightly. His eyes blazed with interest. The Terror had not lied. His talk of radio impulse, like his bomb on Baldwin Island, was no bluff.

There, just one minute before twelve, was a red imprint that one of the tiny needles had made. Four long marks, two shorts, and four more longs. They had been written by a stylus set in action by a wave-length of approximately nineteen meters. They ended just before midnight, did not appear again, and had not appeared before all evening according to the cylindrical chart. As though the Terror had written his signature in blood, those tiny crimson lines on the paper roll were visible proof of his existence.

Agent “X” straightened. He had done what no one else in the city had even thought of doing — made a record of the radio impulse which had exploded the bomb. He had its wave-length now, had proof of the Terror’s appalling cunning. He would set one of his operatives to watching that wave-length at all times, in the hopes of locating the point of broadcast.

He changed his clothes quickly. Then phoned the Hobart Agency and listened in to a report from Bates. But neither organization, though they had worked faithfully all evening, had been able to pick up information valuable to “X.”

IT was the next morning that the Secret Agent thought of another possible source of information. His methods were often strange. Throughout the city and the country he had made acquaintances in odd places. The underworld knew him only as a legendary scourge. The police considered him a desperate criminal. But to many, to the poor, weak, and down-trodden, he had been a friend and benefactor.

None of these knew his real identity. But, going abroad in one or another of his amazing, brilliant disguises, he had made many loyal friends. In the Chinese quarter he was esteemed as a distinguished member of the famous Ming Tong. As Mr. Martin, newspaperman, he had been a friend and benefactor to many newsboys. In the disguise of a ragged tramp he had delved into the most impoverished depths of human society, made contacts with beggars, hobos, and down-and-outers. And often, beneath their dirt and rags, he had found brave humor, courage and shining human worth that shamed the upper rungs of society.

Now, because he was working in the dark against murderous criminals, he thought of a man, a friend of his, who lived always in utter darkness.

In his small car, Agent “X” sped down into the narrow, winding streets of the city’s tenderloin district. Here squalor and poverty showed on all sides. Here smells rose from the cluttered pavements to compete with the mustiness of the buildings that fringed them. Yet, close at hand, only a few blocks away in fact, was a section inhabited by criminals; with gaudy dance halls, drinking dens, gambling joints, and small unlicensed eating places.

On an alley-like street at the edge of these slums, close to this area of tinsel and crime, Agent “X” stopped. He got out of his car, strolled along the narrow pavement in the role of a plainly dressed young man — with no particular destination in mind. But his eyes were alert. He was definitely looking for some one.

The morning bustle of the section had begun. Pushcarts loaded with fruit, vegetables, and sea food rattled by. The streets were filling up with early shoppers, old women with kerchiefs over their heads, young children sent out to buy a few pennies’ worth of food.

The Agent noted all these, but his gaze drifted on. He crossed the alley, came to a wider street at the edge of the criminal quarter, paused at a corner to look in both directions. Then suddenly a flitting smile curved his lips.

A thin, scarecrow of a man with sightless sockets for eyes, was coming down the block. He was walking steadily, surely, along the pavement, with no cane to guide him. His head was tilted back. He was sniffing the cool morning air. Before him, tied around his middle with a piece of string, was a small tray holding a few packets of chewing gum; Agent “X” knew this man.

Thaddeus Penny was his name. Once, disguised as a character, “Robbins,” “X” had helped Penny, saved him from being thrown out of his small furnished room for the non-payment of rent. Since then “X” had often met Penny, and the blind beggar was ever grateful to the man he knew only as Robbins.

Agent “X” walked forward now. Penny was blind, stone blind, having lost his eyesight years before in a tenement fire. But, because of his affliction, his wits and all his other faculties seemed to have grown keener. He could walk about without a cane, could read by means of the Braille system, could identify men by their voices and the minute sounds they made.

THE blind beggar suddenly paused as “X” came opposite. He cocked his head to one side, listening. Intelligence brightened his sensitive, sightless face. Agent “X” moved by, watching. Penny turned around then, looked after him, as though those empty sockets were gifted with some strange second sight. But “X” knew the blind man was receiving impressions through his ears alone. He paused, returned, and as he passed this time, Thaddeus Penny spoke:

“Mr. Robbins!” he said. “I thought it was your step. Now I know — you’re trying to play tricks on me!”

Unhesitatingly, Penny came forward and laid a hand on “X’s” arm. His fingers clasped the Agent’s for a moment in a friendly grip.

“Right, Thaddeus,” said “X.” “You’re out early this morning. I saw you and wondered if I could sneak by — but I might have known I couldn’t. Let’s have a piece of that gum.”

Penny was silent for a second or two, his pale, lined face expressionless. He seemed to be listening — or thinking.

“You didn’t just stop me to say hello or to buy gum,” he said suddenly. “You’re worried about something. You’re breathing faster and not so deep as usual, Mr. Robbins. Anything the matter?”

Agent “X” threw back his head and laughed — something he seldom did, grim manhunter that he was. But Thaddeus Penny’s amazing powers of concentration and deduction always amused him.

“It’s lucky, Thaddeus,” he said, “that you don’t go in for crime. If you did, nobody would be safe!”

“Crime!” said the blind man. “So, that’s it! You’re always talking about crime, Mr. Robbins.” Penny smiled knowingly, staring vacantly into space. “I once told you you were a detective, you remember. Then I took it back, because you don’t act like any detective I’ve ever known before.”

“How do I act, Thaddeus?” asked Agent “X” suddenly. Blind as Penny was, he was one man whom Agent “X” suspected of knowing more than he admitted. “X” could come to him in any disguise. It was his voice and step that Penny recognized. But it sometimes seemed that Penny, with his remarkable brain, sensed the strange, magnetic qualities of Agent “X,” also.

“You act like a man,” said Penny slowly, “who sees farther than any eye could reach. And you act like a man who has a lot to think about.”

“The latter is true, anyhow, Thaddeus. I’ve got a lot to think about. And this morning I’m thinking about crime, as you say.” The Agent sank his voice lower then, so that no one passing on the street might hear. “There’ve been a great many robberies and murders this past week, Thaddeus, a great deal of crime in this town. Some say the police are being bribed. Others say they’re scared. I don’t know which is right. But there must be criminals who are getting rich and fat. I’d like, for private reasons, to know who they are.”

Thaddeus Penny nodded slowly, understandingly. A slow smile overspread his face, a knowing smile as though he suspected the purposes and motives of his friend Robbins and approved of them.

He cocked his head to one side again, listening to all sounds on the block. Then he drew “X” against the wall of a building, leaned close and spoke, his voice hardly more than a whisper.

“I get about a bit,” he said, “and sometimes ears are better than eyes. Sometimes I hear and remember things that others quickly forget — because when a man’s blind all he has to amuse him are his thoughts. He plays games with himself — tries to fit things together.”

Penny smiled and nodded slowly, tapping “X’s” arm. “Maybe you’ve heard of a fellow named Gus Sanzoni. He’s been quiet for years, isn’t rated as much of a big shot — but they say he made a pile of dough during prohibition. He had cookers working for him on a hundred stills and he had a mob. But when money comes easy, it goes easy, too. I heard that Sanzoni gambled away everything, lost his mob and his power, and had only a night club left. Then, lately, some of the fellows that used to work for him are calling him a big shot again instead of a cheap punk. There’s ‘Dutch’ Wilken, Mateo the Moocher, and ‘Little’ Dellman among ’em. They seem to feel frisky lately. The girls say they’re flashing big rolls. Don’t ask me how they get ’em. But when a crook has big money, there’s always blood on it. And Gus Sanzoni don’t pay men just because they’re his pals.”

The eyes of Agent “X” shone brightly as he listened. Bates and Hobart had men drifting through the tenderloin section, probably within a stone’s throw of him now. Yet they had learned nothing. The lips of the underworld had remained closed to them. It had taken the sharp ears of a blind beggar to hear the whispers that the Agent wanted, the rumors, that might send him in desperate, daring conflict against the menace that lay like a curse of waiting death over the whole great city.

Chapter X

HE thanked Thaddeus Penny quietly, withholding from his voice all trace of the deep excitement he felt. Yet Penny nodded wisely and laid a hand on “X’s” arm.

“That’s the news you wanted, isn’t it?” he said. “It sort of fits in with something you had in mind. You’re breathing fast again. I can almost hear your heart beat. But don’t go and get into trouble. Even if you’re a detective stay away from Gus Sanzoni. He’s like the rats that come out from the cellars at night. They run if you go right after them — but like as not they’ll turn around and bite you in the back afterwards.”

A thin smile twisted the lips of Agent “X.” “Don’t get into trouble,” Thaddeus Penny had said. But trouble was the Agent’s daily bread, trouble of the most bizarre and violent sort — trouble that other men would flinch from, but which he had grown hardened to.

“I’ll take care of myself, Thaddeus,” he said quietly. “Don’t worry about me. Suppose you give me a package of that gum.”

Agent “X” tossed a nickel into the old cigar box which Penny used as a tray; but along with it he dropped a crumpled five-dollar bill. This maneuver didn’t escape Penny’s sharp ears, however. The faint rustle of the bill was audible to him.

“There you go again, Mr. Robbins, giving me a cash hand-out! I won’t take it, I—”

“Your tip was worth it, Thaddeus. If you don’t need the money, give it to some friend who’s in a hole. I’ll be seeing you later. And thanks again.”

Agent “X” walked swiftly away from the blind beggar. He passed one of Jim Hobart’s men sauntering toward the tenderloin. But the detective didn’t guess for a moment that the person he’d brushed was the power behind his own employer, the man he had to thank for his job and his pay.

In his small, fast car again, “X” sped uptown. Thaddeus Penny had given him a tip which demanded instant attention. The Agent parked his coupé, this time, close to a wide, luxurious drive bordering the river. Not far away was the yacht club where was anchored Monte Sutton’s yacht, the Osprey, and where Mayor Ballantine had tried to forget his troubles in an atmosphere of glamorous gaiety.

But for the moment Agent “X” had decided to tackle the menace that hung over the city from another angle. He had gone to the municipality’s highest executive without accomplishing anything except the crystallization of his own belief that something was radically wrong.

Later he had found the Terror’s document in the mayor’s home. Now he would delve into the lowest depths of the criminal underworld — in an effort to trace down the Terror’s men and make contact with the Terror himself.

Closing and locking the door of the coupé, “X” walked swiftly down a side street and stopped at last before a high brick wall. On the other side of this the gables and peaked roof of an old house showed. Even at a distance there was an air of desolation about the place, an air of disuse and decay.

“X” stepped through a hedge of sparse evergreens. His form blended with the shadows along the wall for a moment. A key grated in an ancient lock. A rusty gate swung open, closed softly — and Agent “X” was in the mysterious, statue-strewn rear yard of the old Montgomery Mansion.

He crossed it quickly to the back of the house that had been closed for years because of the bitter litigation of heirs. Here he descended a flight of stairs to a basement entrance, went inside and climbed more stairs to a butler’s pantry.

Under his pressure on a secret lever, one of the big pantry shelves swung out. A door was revealed here, with a large room behind it, a chamber that no one except an architect going over the cubic space of the house would ever suspect. Agent “X” was in a hideout where none had ever been able to trace him.

He went at once to a series of metal cabinets. Here were perhaps the most complete criminological files in the country. Here was data on famous criminals and lesser-known ones that even the police did not possess. Here were odd facts and strange human sidelights which aided the Secret Agent in his amazing work. Fingerprints and Bertillon measurements were included. The files had a cross index system, the result of painstaking hours of labor on the Agent’s part. He quickly drew out a small envelope containing the life history of Gus Sanzoni, the man of whom Thaddeus Penny had spoken.

All the facts were given here, many of which “X” remembered. But he wanted to check up and make sure. The Gangster’s first steps in crime were recorded; his early thefts as a parcel snatcher. His leadership of a gang of hoodlums. His rise to power during the prohibition era when his business sharpness and brutal tactics made him the head of one of the city’s largest bootleg rings. Then the loss of his fortune and his decline into comparative obscurity as the owner of a night club when the repeal law was passed. Names of Sanzoni’s mobsters were included.

The Agent quickly found an item that interested him. Two of Sanzoni’s former lieutenants, Floyd Kittredge and “Bugs” Gary, were in prison. They had been held in connection with a cop shooting during a liquor raid. Bugs Gary’s time was almost up. He had only a month more to serve. His term had been shortened owing to good behavior in prison.

Agent “X” quickly memorized the data on Bugs Gary. It wasn’t quite as complete as he would have liked, yet it would serve his purpose. He left his hideout twenty minutes later, satisfied that he had a definite working plan.

THAT afternoon a long-distance call was received in Washington by a man who preferred to be known only as K9. He was an official of the government, so high that a mere suggestion from his lips became a command elsewhere.

For five minutes Secret Agent “X,” speaking in a low, guarded voice, and using a private wire straight to Capital Hill, talked to K9. K9 listened and agreed.

The governor of the state in which crime had so strangely broken out and was racing unchecked, received an official government message within the hour. It suggested immediate clemency for the ex-gangster, Bugs Gary.

This message was transmitted to the warden of the prison where Bugs was held. From then on, the wheels of the official machinery, which Secret Agent “X” had set in motion, moved speedily.

Bugs was called into the warden’s office. He was told that because of good behavior, the governor had seen fit to shorten his sentence. He was handed his pardon, told that he was now a free man. And, slightly dazed, hardly believing his good fortune, he walked out of the prison gates, with money in his pocket and a new suit of clothes provided by the state on his back.

He didn’t notice the inconspicuously featured man in brown, who at once trailed him. The stranger’s manner was so casual that even a criminal twice as clever as Bugs would not have suspected he was being followed.

Yet when Bugs went to the station and swung aboard an express bound for the city, the man in brown was on the car, too. He took a seat close to Bugs, keeping the ex-gangster under surveillance through a tiny hole torn in the newspaper which he held before his face.

There was more than mere curiosity in the stranger’s eyes. There was studied appraisal. He was watching hawk-eyed every gesture Bugs made. When the gangster asked the conductor a question about the train schedule, the man listened to each syllable of the criminal’s voice, storing it away carefully in his memory. At the big Union Depot where Bugs Gary alighted, the stranger strode behind him for some distance, noting the gangster’s walk.

Bugs paused for a moment before the windows of a station haberdashery shop to eye admiringly a checked suit of latest cut, and a collection of startlingly bright ties. It was then that the man in brown brushed against him.

Bugs felt a slight prick in his arm, hardly more than as though some tiny splinter of wood mixed with the cloth of his suit had been driven in. He heard the man in brown apologize for being clumsy, then move on — and Bugs thought nothing of it.

But a moment later his legs began to rock and sway under him. Details of the building and people around him began to blur. Bugs opened his mouth to give a frightened cry; but no sound came. His tongue, like his legs, seemed to be out of commission. With a grunt, Bugs Gary collapsed to the station floor and lay there with a surprised expression on his heavy ugly face.

THE man in brown came instantly to his side. He had whipped a black case from his pocket. He looked deeply concerned. A crowd began to gather. The man in brown spoke authoritatively.

“Stand back! Give this man some air, I’m a doctor. He appears to have had a heart attack. Some one help me get him to my car outside. We’ll take him to a hospital at once!”

A station attendant gave the required aid. Bugs Gary was carried limply to a small, compact coupé parked outside the station. A few slight dents in its sleek enamel which were carefully patched bullet holes didn’t attract the attendant’s attention. The man who had said he was a doctor drove swiftly away with the unconscious gangster at his side.

But he didn’t go to a hospital. Instead, he drove swiftly to a garage back of a small suburban house. Once inside, he closed the garage door, and carried Bugs through a passageway to the house itself. This was empty. It was another of the Agent’s hideouts, and he had accomplished the capture of Bugs Gary by a means he had often used before — the injection of a quick-acting, harmless anesthetic.

Bugs came to after awhile. Still in a dazed state, he found himself handcuffed in a chair and facing a man whose eyes had an uncanny, magnetic intentness. He was terrified at first, but the stranger soothed his fears. No harm would come to him if Bugs answered a few simple questions about his past. Because he couldn’t seem to help it under the steady stare of those burning eyes, Bugs Gary did so.

The stranger listened carefully, as much, it seemed, to the tones of his voice as to his words. He made minute examination of Bugs’ face and figure, asked him what sort of clothes he liked to wear, his eating preferences, and other odd, personal questions.

At the end of it, the stranger offered Bugs a drink of liquor which the gangster eagerly accepted. He finished it, licked his lips and once more dozed off into dreamless slumber. Though he didn’t know it, he was due this time not to wake up for at least thirty-six hours — unless Agent “X” chose to administer a reviving stimulant…

As dusk was again falling over the city, a man, who looked for all the world like Bugs Gary, stepped out of a taxi and swaggered toward the lighted doors of the Montmorency Club. This was the infamous underworld dive whose present proprietor was Gus Sanzoni.

Evening papers had mentioned the fact that Bugs Gary had been pardoned. Whispers had run through crookdom. Bugs would surely be coming back to his old haunts.

The doorman of the Montmorency Club wasn’t surprised therefore at the sight of the dapper figure in spats, checked suit and bright tie who came forward arrogantly.

“If it ain’t Bugs,” the doorman said. “I saw about you in the paper a half hour ago. I thought you’d be coming around to see the boys. You look like a million dollars, Bugs. They must have fed you good up in the Big House.”

The man who looked like Bugs flicked ashes from his cigarette and made a fitting wisecrack. All the while he was watching the reactions of the doorman intently. Inwardly he was elated. His disguise made old acquaintances recognize him in the way he wanted. The doorman of the Montmorency Club had no inkling that this man who seemed to be Bugs Gary, was really Agent “X,” famous criminal investigator, come to risk death in the headquarters of an underworld czar.

Chapter XI

A CHECK girl took his hat and cane. A strident band was playing beyond the club’s polished dance floor, warming up for the evening’s work. Few patrons had arrived as yet. It was still too early for slummers. The food at the Montmorency wasn’t inviting. It was the hectic, sinister atmosphere of the place that brought men and women from the after-theatre crowds to get a thrill by rubbing shoulders with the underworld.

But some of Sanzoni’s hangers-on were in evidence. Two dapper, flat-chested men, with twisted smiles, nodded instantly as Agent “X” came through the door. They were at a table, liquor glasses before them. One got up.

“Bugs Gary himself!” he said. “We heard about you getting on the right side of the governor. Welcome to the old joint, Bugs!”

Behind his outward calm, the mind of Agent “X” was active. His pulses hammered. He knew he was in a dangerous spot. His facts on Bugs’ past were brief. He didn’t even know the names of these two. Any moment he might say or do something that would betray him. Then their smiles would change to snarls. Their hands would reach for guns.

He wasn’t afraid of death. He had rubbed shoulders with the Grim Reaper too often. But he knew now what the strange, sinister mystery that menaced the peaceful life of the city was — knew the horror of those NP bombs. The sights and sounds of the razing of Baldwin Island had etched unforgettable memories in his mind.

He grinned expansively, advanced and shook hands with the gangster. “How are you, boy!” he said, using the accent of Bugs Gary that he had so carefully learned.

“You got your glad rags on, Bugs. You look as if you’d struck it rich in the Big House.”

Agent “X” waved a bejewelled hand. “I had a little cash salted away. I thought I’d treat myself to a blow-out now that I’m back on the town.”

“Come and sit down, Bugs? The drinks are on us.”

A waiter came to take his order; but before the drinks arrived, a glamorous blonde woman came through the door at the end of the big room. She made straight for the table “X” was at, and one of the men beside him spoke.

“There’s Goldie, now. She’s spotted you right off, Bugs. You always did have a way with her!”

The two laughed significantly, eyeing “X” sharply. And a sudden sense of danger swept over him. There was something in their manner that he didn’t quite understand. He had heard of Goldie La Mar, notorious night club hostess and underworld queen. But if she had been an especial intimate of Bugs, his files bore no record of it. His heart beat faster as the woman approached.

Seen closer, her glamorous beauty resolved itself into skillful make-up. Her eyes were heavily mascaraed, shadowed underneath. Her face was powdered thickly, her lips rouged into a dazzling but unnatural curve. Yet she walked with the free-swinging grace of a female panther. She was still a handsome, alluring figure of a woman, sure of herself and of her charms.

“Bugs!” she said. “Ain’t this grand! It’s like old times to see you back. Your pals thought of you — even when you went away. It seems a long time. How’s the boy?”

“Never better. And glad to be back, Goldie,” said “X.”

He watched the woman sharply. Her eyes held his, lingered, then seemed to find some lack. She pouted, dropped her lids a moment. The orchestra struck up just then. The woman took a step closer, smiled disconcertingly.

“Let’s see if you can still hoof it, Bugs — the way you used to. Or did you forget how to shake your dogs while you were breaking rocks?”

It was a command, not a suggestion. Goldie was already close, her powdered arm lifted to his shoulder. He encircled her waist at once, danced out on the polished floor. The woman’s heady perfume was in his nostrils. Her supple body was close to his; yet he felt intuitively that he was in the presence of a dangerous being, whose smiling sleekness hid sharp, cruel claws.

Out of earshot of those at the table, Goldie La Mar spoke close to his ear in a husky drawl that held a lingering caress. “What is it, Bugs, you ain’t sore that I hitched up with Gus? You didn’t think a girl like me could wait around for a mug forever? You were a good guy, Bugs, but when they railroaded you away, it looked like you was gonna stay for good. I’m a girl who likes nice clothes and things, and Gus is a good provider.”

THE beating of the Agent’s heart increased. For a moment he was silent, gathering his faculties. The truth came to him. He had ran full-tilt into a complication. Goldie La Mar had been Bugs Gary’s moll before he went to jail. Now she was Sanzoni’s. He must watch his step. Yet perhaps he could make use of the situation, find out the things he wanted to know.

“A guy forgets how to treat women when he stays in stir,” he said. “You don’t see ’em there. But watch me warm up if I stick around this joint. It looks like the old days, Goldie, when the boss was running the stuff and sellin’ it to the suckers at fancy prices.”

Goldie La Mar laughed a brittle, significant laugh. “It’s better than the old days, Bugs. You’ll like it. There ain’t no blue-nosed mugs snooping around to spoil the fun. There’s plenty of dough and the liquor’s better than it used to be. A girl can drink without growing barnacles inside.”

“Sanzoni’s running liquor still then?”

“Hell, no! There ain’t no money in that — when every soda joint has a liquor stamp.”

“What is his racket?”

Goldie La Mar laughed again, mysteriously. “Never mind about that. He’s got a lot of things in the fire. But whatever he does is O. K. at City Hall. I guess the guys in the old days didn’t know what a wire was or how to pull it.”

Agent “X” almost betrayed himself by the tenseness that crept over his body. Then, smiling down at her, he spoke slowly, casually. “Gus always did know how to grease the going, Goldie. You mean he’s got the mayor on his side now?”

For a bare instant a glitter crept into the limpid sheen of Goldie La Mar’s mascaraed eyes. But the Agent’s bland smile disarmed her. She nodded.

“He’s got protection — what I mean. The mayor eats out of his hand. And he keeps the dicks in their places. Gus is gonna be the biggest shot there is. And you can’t blame a girl like me for fallin’ for a guy like that, can you, Bugs?”

Agent “X” forced himself to smile again; forced himself to hide the tense excitement he felt. He was getting nearer the truth now. He spoke softly in the voice of Bugs Gary.

“I can’t blame you, Goldie. That’s right. You always did know how to pick ’em. Look at me! But one of these days you’ll get tired of Gus and—”

Goldie shook her gleaming head coyly. “You and me can be good friends as long as Gus don’t get wise,” she said. “But I ain’t getting tired fast of a mug that pulls in fifty grand a day.”

Agent “X” swung the woman into the steps of a fast foxtrot, leaning over her a bit to hide his face from her sharp gaze. He wanted to think.

The dance ended. Agent “X” took the woman back toward the table where Bugs’ two former pals still sat. They applauded loudly.

“You and Bugs make a good team, Goldie! It’s too bad Gus can’t dance like that, too.”

Goldie put her finger to her lips and rolled her eyes. “Gus can do other things,” she said mysteriously. “And you boys better watch yourselves.”

The instant sobering of the two gangsters faces showed the respect in which they held Sanzoni. They assumed poker expressions, fingered their glasses.

“Better go in and see him, Bugs,” said one. “He might get sore if you hang out here without letting him know.”

“Yes,” said Goldie, “run along, Bugs, but act decent. Gus is used to bein’ treated right these days. He makes all the boys toe the mark.”

“X” hesitated a moment, looking about him.

“The door at the left,” said Goldie. “He’s got a new hangout now. Go through the hall and up the stairs. His place is right ahead. But knock before you go in.”

AGENT “X” followed her directions. He was like a man walking on glass. But the eager, questing light of battle was in his eyes. He entered the doorway at the left of the dance floor, passed through a corridor, mounted a flight of luxuriously carpeted stairs, and knocked at the door before him. A wheezing voice bade him come in.

“X” did so, opening the door and entering a chamber that was a cross between an office and an elaborately ornate den. Great leather chairs stood about. Expensive woodwork made brownish reflections under shaded lights. A period-design of table stood in the center of the floor. And behind this a man sat.

He was a big man, with rounded shoulders and a bull-like neck that hung in flabby rolls over his collar. His small eyes were sunk in pouches of flesh. His lips were moist, red spots in a pile of blubber.

“X” had seen pictures of Gus Sanzoni. This was the man; but he had put on weight obviously. Prosperity had padded his massive frame with an excess of pendulous, unwholesome fat.

He did not seem surprised to see Bugs Gary. He held out a flabby hand, smiled, and waved to a chair. But his fingers were fishily cold, and there was no friendliness in his smile or in the brittle glitter of his small eyes.

“Sit down, Bugs. The boys told me about you getting out. I figured maybe you’d turn up.”

Looking at the man before him, Agent “X” felt that he was in for a battle of wits; that he was already on the mat before a relentless, masterful personality who would be difficult to trick or bulldoze.

Agent “X” smiled, met the glittering eyes of the other, all but out of sight in the flesh around them.

“Couldn’t stay away,” he said lightly. “A guy gets lonely for his old pals in stir.”

A laugh that began as a wheeze sounded in Gus Sanzoni’s throat. It rose until it was a bubbling peal of humorless mirth that filled the room.

“You like your old pals, Bugs!” he panted. “You got all dolled up just to meet ’em, eh, Bugs? You came back as quick as you could when they let you out!”

Agent “X” nodded, still smiling, but with the knowledge that the man before him was making sport of him for some reason of his own. Then suddenly Gus Sanzoni seemed to rise in his chair, tower like an unwholesome, menacing hulk; his dark eyes aglitter. He leaned forward across the table.

“Don’t pull that stuff on me, Bugs,” he wheezed. “Don’t think you can soft-soap Gus Sanzoni. You didn’t get out of the Big House for nothing. You didn’t come here because you loved us.”

There was silence in the room; tense silence while Agent “X” stared at the other waiting. Gus Sanzoni’s fat, almost shapeless hands spread out on the table like a bloated spider’s claws. The movement of his small red mouth was venomous.

“I’m onto you, Bugs. They let you out of the Big House for a purpose. You heard I’d taken Goldie. You’d heard I was playing a new racket, and you saw a chance to make some dough for yourself, and maybe square things up. Who’s payin’ you to be a stoolie — an’ spy on me?”

Agent “X” was for a moment speechless. This was a twist he hadn’t anticipated. Gus Sanzoni, far from the truth, was yet near enough to upset all of “X’s” plans. His disguise had worked; but it had gotten him in as deep as though he had come as an agent of the law.

“You musta gone off your nut, Gus,” he said. “I ain’t no stoolie. I—”

“None of your dirty lies! I ain’t got time to listen to ’em. There’s only one thing I want to know. Who’s the guy that got the warden to pardon you?”

“Why the governor, Gus. You know the governor has to—”

“Yeah. And who asked the governor to do it? Who’s got you on his payroll as a stoolie? Answer me that!”

“You’re talking crazy, Gus. You know Bugs Gary wouldn’t never doublecross—”

“O. K.,” said Sanzoni evilly. “You’re a tight-lipped guy! They got you fixed nice! But I got ways to make mugs loosen up when I ask ’em things — and I’ll make you beg for a chance to talk!”

“X” didn’t see the gangster move. But a buzzer sounded faintly somewhere. It testified to the fact that there was a button under Sanzoni’s foot on the floor. Instantly a door at the end of the room opened. Two flint-eyed men with sawed-off shot guns entered. Then, from the sound behind him and the faint draft of air on his neck, “X” knew that others had come in from the rear. He was surrounded, threatened with instant death if he made a move, in the stronghold of as cunning a criminal as he had ever come across.

Chapter XII

SLOWLY he turned so that he could see both pairs who menaced him. Those at his back were the same two he had set at table with a moment before — Bugs Gary’s pals. But their faces were dead pans now. Their hands gripped black automatics. They would shoot at the merest nod from Sanzoni, send a withering stream of slugs at his body. For that was the law of the underworld — obey the big shot — murder a pal in the interests of one’s own career. Like the gray rats that Thaddeus Penny had mentioned, each was out for himself alone. And because Sanzoni had money, influence, they would murder callously at his behest. The gangster’s harsh, wheezing chuckle sounded again. “Here are your pals, Bugs. You came to see ’em! Look ’em over! They got a welcome for you — a dose of lead. You’ll be glad to talk when they start working on you. Maybe you’d rather unbutton your lip now — and tell me what I asked.”

Agent “X” was silent. Whatever he said would be held against him. He couldn’t tell Sanzoni what the man wanted to know. Better keep still, and wait for a possible break. But none seemed coming. Sanzoni was experienced in handling desperate, murderous men. He was taking no chances.

“If he goes for his rod, boys, give it to him where he stands. Frisk him, Regio.”

A fifth man started toward “X” to disarm him. The Agent’s eyes burned somberly at this. There were things on his person that must not be discovered — his strange devices that he carried, his gas gun which would give him away, make Sanzoni suspect that he was not Bugs Gary at all. Sanzoni spoke as the man Regio came forward.

“The boys will take you downstairs, Bugs! They’ll work on you there. Shoot your fingers off — like they did Mike Barney’s. Maybe you remember Mike! And by the time you’ve lost a couple of thumbs you’ll be willing to talk!

A picture flashed through “X’s” mind. A picture of a criminal he had once seen, Mike Barney, trying to light a cigarette with shapeless, crippled hands, a silent, bitter man, reluctant to say what sort of accident he had met with. Now “X” knew.

There was no limit to the unholy cruelty of the fat fiend before him. Sanzoni was laughing, taunting him.

“You won’t be such a headliner with the janes, Bugs, when your hands look like chewed-off tree stumps. Mike Barney’s gal left him when the boys got through with him. Janes is funny that way. They like pretty things — and a guy with no fingers ain’t pretty.”

An involuntary tensing of the Agent’s muscles made the men with the guns step closer. With a curious, speculative expression in his eyes, “X” estimated the angle that the black guns were pointing. They were aiming low in true gangster fashion. A thin smile curved his lips.

At that moment he heard the brittle laugh of a woman close by, blending with Gus Sanzoni’s. He looked up. Goldie La Mar stood in the doorway. Her hands were on her hips. A mocking light was in her eyes:

“You’d better have stayed in the Big House, Bugs. You came asking for trouble — and you’ve found it!” She turned to Gus Sanzoni “He wanted to know too much when I danced with him a while back. You’ve got his number O. K. He’s just a dirty stoolie.”

The gangster, Regio, was close to “X’s” side now, reaching out to search him — and find the things that would betray “X” as a far more dangerous enemy to Sanzoni than Bugs Gary could ever be. The muzzles of the mobster killers’ guns were held steady, ready to send lead at “X” if he did not submit to Regio’s frisking.

An attempt to escape now seemed suicidal; yet, in the fraction of a second before Regio’s hands entered his pockets, Agent “X” went into swift, death-defying action.

He lunged forward, sweeping Regio out of his path with one flailing arm. A surprised wheeze came from the lips of Sanzoni. The gunmen killers, obeying the orders their chief had given them, pressed triggers. In that brief instant when he flashed through space, bullets thudded against the Agent’s body.

BUT he didn’t cry out, or collapse. He hurtled straight on. His movement hadn’t been a wild plunge of sheer terror, the panicky, maneuver of a fear-crazed man, as it seemed. It had been a calculated, timed action, based on the confidence of a defensive device which Agent “X” had carried when he came here. This was his special bulletproof vest — a shell of case-hardened manganese steel, with a raw silk stuffing and an outer shell of light-weight duralumin. It was worn like a vest. Once before it had saved Agent “X” from annihilation, at the hands of gangsters.

It worked now. The lead from the sub-calibre machine guns missed him except for a few glancing blows. The .45 slugs from the automatics penetrated the outer duralumin shell, but flattened their noses against the inner steel.

Quick as a flash Agent “X” was on hands and knees before an empty electric wall socket near the floor.

The gangsters, thinking their salvo had mortally wounded him, and hoping to get a dying confession from his lips, held their fire now. This was what “X” had counted on. With a lightning movement, he drew something from his pocket. It was a small, curved bit of wire; a simple, but effective device that had served him well before. He thrust this into the socket terminals under the very nose of Sanzoni’s mob.

There was a sputter, a flash of violet light, and every bulb in the Montmorency Club was extinguished as the fuses blew; short circuited by “X’s” wire.

In the ensuing darkness Goldie La Mar screamed shrilly. Sanzoni broke into wheezing curses. The gangsters who had been posted to torture or kill Agent “X” bumped against one another and grappled fiercely.

Agent “X,” crouched low, could see their silhouettes against the glow of a street light that filtered through a window. A gangster came straight toward him. Agent “X” leaped up, struck a chopping blow to the man’s chin, and heard him collapse.

He sprang toward the door then. Sanzoni stepped around from behind his desk and the fist of Agent “X” flashed out to give the fat gangster a breath-jarring punch in his obese stomach.

Sanzoni collapsed gasping over his desk, and “X” sprang through a doorway into the corridor. Pandemonium had broken out in the club now. Shouts, screams, the excited cries of men and women mingled.

Straight across the big ballroom Agent “X” sped. He had verified what he had come to learn; verified the truth of Thaddeus Penny’s report that these were the men who were spreading terror and death over the city. The same men that Mayor Ballantine was giving protection to. It meant that Sanzoni was the ally of the Terror.

He ran down the stairs, saw the form of the doorman coming in to see what all the excitement was about, and leaped past him into the street.

In a moment he had merged with the darkness. And the night around him seemed heavy with mystery; heavy with the sinister threat of the thing he had learned.

He went to one of his hideouts and paced the floor, facing squarely the problem he was up against. He struggled silently, as a chess player might struggle, trying to anticipate and forestall the play of his opponent.

It was obvious that the impulse sent out to raze Baldwin Island operated only that one bomb. Those other silent eggs of death lay waiting, hidden, for the awful call that would bring them to life also. That call might come on the same meter number — merely another series of dots and dashes — or it might come on an entirely different one. And where were the bombs themselves? How could he find them, now that he knew how the Terror had hidden the one on Baldwin Island and knew also the identity of the Terror’s gang?

He got a city map, marked off all the strategic points where bombs would do the most damage. Yet he knew this was only guesswork. It would take days, weeks perhaps, to go over these spots — and meanwhile death and horror hung over the city. Yet if he could only find one bomb, see how the thing worked, learn the exact nature of the new explosive element, perhaps—

The Secret Agent’s mind, functioning like some delicate, precise machine, hit suddenly upon a startling conclusion. He believed he had divined one move at least that the Terror might make. One move that, in the light of facts “X” had unearthed, seemed logical and inevitable. To test this belief Agent “X” stood ready to face the thunderous menace of high explosive once more.

Chapter XIII

LATER that night, between the hours of two and three, Secret Agent “X” approached the Montmorency Club a second time. Sleep was out of the question for him. Restless, dynamic forces drove him on, would not let him be quiet while destruction, fear and horror threatened the community. The thought of those hidden eggs of death, silent and waiting somewhere in the dark city, was a ceaseless spur to his energies.

Since verifying the fact that Gus Sanzoni’s gang was active in the crime wave now engulfing the city, Agent “X” had instructed Hobart and Bates to have their best men watch the doings of the gang.

Through both organizations, working independently, “X” had learned that most of Sanzoni’s men would be out tonight, ravaging certain sections of the city in a series of bold robberies. This meant that Sanzoni’s headquarters in the Montmorency Club would be comparatively deserted. It meant that the stage would be set for Agent “X” to play another surprising role.

Once again he had disguised himself, but not as Bugs Gary. His clothes were black now. His whole face had a swarthy hue. Amongst the shadows he appeared to blend with the night itself. He looked like a burglar or sneak thief once more, as he had on the night he’d gone to Mayor Ballantine’s home.

He drove to within a block of the club, left his car parked, and proceeded on toward the spot where the evil Sanzoni, like a fat, poisonous spider, spread his webs of crime. But “X” knew more about the gangster now. He knew that Sanzoni, for all his evil ways, was under the sway of a greater criminal than himself; knew that he was the cat’s paw that pulled the chestnuts out of the fire for the Terror. And Sanzoni, who divided his loot with the Terror, must have some way of communicating with his superior, some way of handing over the spoils of his bloody work.

This, however, wasn’t the Agent’s reason for returning to that place of sinister repute. He had another, more daring motive, based on the startling deduction he had made.

It was late, long after midnight, yet the orchestra in the Montmorency Club was still blaring raucously. Tipsy couples were still moving around the polished dance floor. A few late-comers were still arriving, nighthawks who made a practice of flitting from one gay dive to another.

As Agent “X” shuffled past the front of the club, somber and inconspicuous in his dark clothes, a gay foursome stepped from a limousine. Two youths in high silk hats; the girls in evening wraps, with painted, powdered faces wreathed in smiles. Slummers from uptown. Members of society, possibly, come down to rub shoulders with the city’s underworld.

He heard their empty laughter as they hurried into the vestibule. Their mirth would change to gasps of fear, they would run from the place, if they knew what he knew — and suspected the thing he had come to inquire into.

He didn’t go to the club’s front entrance. Its tawdry, gilded portals were not meant for such as he appeared to be. The doorman, who hours before had welcomed him as Bugs Gary, would order him away now.

A grim smile twitched the Secret Agent’s lips. Like a flitting shadow he moved around the side of the building, pausing at a basement doorway. This was below the level of the kitchen. Yet a dim light was burning somewhere inside. He would need all the caution at his command in the thing he planned to do.

He took his kit of special chromium tools from an inner pocket, selected those he needed, and went to work skillfully on the lock. In a moment, under the probing pressure of a small goose-necked bit of steel, it clicked back and the Agent opened the door. He found himself in what had formerly been a luxurious speakeasy. But now it was closed. Now the club had moved upstairs, screaming its tawdriness to the whole world, in renovated quarters above.

Behind the speakeasy were chambers which might contain sleeping quarters for some of Sanzoni’s men. “X” did not explore these. Basing his actions on a hunch he had arrived at, he searched for and found a door that led to the building’s cellar.

As he opened it, and moved down a stairway toward the dusty room beneath where a light in a wire cage burned, he heard the clanking of a shovel. He reached the foot of the stairs and crouched.

A MAN’S shadow lay like some fallen monster across the floor. It was the shadow of the janitor, fixing the furnace, keeping steam up, that revelers above might have tropic heat.

Agent “X” crept toward him swiftly, silently. When the man turned at last to put the shovel away, the black figure of “X” was directly at his elbow. A gun in “X’s” hand was pointed straight at his head.

The cry that the janitor started to give was stifled utterly by the jet of gas that spurted from the gun’s muzzle into his open mouth. It was harmless anesthetizing vapor that would merely keep him unconscious for a period of time. He collapsed soundlessly to the floor.

“X” gathered him up quickly, took him to the far end of the cellar room, and laid him on a pile of old burlap. Then he began the quick, shrewd search of the building’s basement — which was his real purpose in coming.

For the Secret Agent’s amazing deductive faculties had led him to the conclusion that one of the nitro-picrolene bombs might be hidden here.

It was a spot where a man of the Terror’s ruthless, systematic character would appear to have reason for laying one of the eggs of doom. Gus Sanzoni was working for him, gathering in the loot to be divided with his master. Sanzoni was a greedy, unscrupulous criminal, a man who would turn on his boss, double-cross him if the chance came. He had not hesitated to double-cross Bugs Gary, take his girl away while he was in jail, and put him to torture when he came back.

And surely the Terror, whoever he was, would make certain that he could wipe out Sanzoni any instant he chose. What better means than concealing a bomb directly under Sanzoni’s stronghold?

So certain was “X” that this deduction was right, that he had come prepared with special equipment. Besides his regular tool kit, he carried in one pocket a small leather case containing instruments as compact as they were powerful.

The bomb hidden in the brick building on Baldwin Island had given him his cue. It had been cemented in the wall, and “X” knew that the criminal mind ever works in a routine manner. The gang who laid the Terror’s bombs for him would surely use the same means again.

He took a powerful flash and chisel-like scraping instrument from his pocket. With these he set to work. He began systematically at the farthest end of the cellar room. The beam of his light was like a round probing eye. It crept along the soot-blackened walls from floor to ceiling. Again and again at any spot that even slightly aroused his suspicions, he scraped with his edged tool.

Slowly he progressed forward till he had covered one side of the cellar. He went to another, searched over every inch of that without results. A third side followed, and still Agent “X” was persistent, still undiscouraged.

Several times he came to places on the plaster that stirred his interest. Either the soot didn’t seem quite as black or something about the surface held his attention. At such times he took a small watchlike instrument from his pocket. It had a tiny needle on its face, slender as a hair. It was a delicate magnetic galvanometer, fashioned to detect minute electric currents produced by the presence of metals.

He pressed this against the suspicious spots, watched the needle eagerly. Once it swung sharply, making his pulse quicken. But a brief scratching on the surface exposed a hidden water pipe.

He went on to the cellar’s fourth side, and here he found a small door, held fast with a padlock. This he undid easily. Inside was a square, cool wine cellar, with hundreds of bottles stored away in straw-filled bins. Here was the wine that trickled down the thirsty throats of the criminals and slummers in the gay rooms overhead.

The Agent’s eyes gleamed. This room was locked, hidden away from ordinary prying eyes. It was a likely spot to look. He began searching the walls quickly, and almost at once he found a place where the layer of accumulated dust seemed a shade too thick.

To his eager, observant eyes it appeared that this dust had been sprinkled there. His sharp tool scraped it loose. He found that the plaster beneath was whiter, fresher — found that it was a spot like that on the wall of the room on Baldwin Island, where he and Betty Dale had faced awful death.

And when he touched the galvanometer against this spot, the tiny hair-like needle swung instantly upward and remained like a trembling finger of warning. Tense with eagerness, knowing that he might be close to a bomb as terrible as any existing in the world, Agent “X” paused a moment.

LISTENING, he could hear, faint and far away, the throbbing pulse of the dance orchestra, hear the vibration of moving feet. Men and women were dancing over a veritable hell that they did not even suspect — dancing on Death itself, that lay silent and hidden in that dark cellar.

The Secret Agent set to work quickly. There was an electric bulb above him. He unscrewed it, put a plug in with a long cord attached, and inserted this plug into the handle of one of the tools he had brought. A miniature electric motor, sealed in a sound-proof shell, began to whirl. A cutting point with a rubber cap around it spun at the drill’s end. Agent “X” pressed this and the rubber deadened sound against the wall at the fatal spot. This was one of the devices with which he had come prepared, anticipating that he would have to cut through cement.

His sharp, diamond-set drill ate the concrete away. But in spite of all his precautions, it made a faint whining sound — a sound that he knew might reach other ears and attract attention. Because of this he was alert, listening and watching.

But when his drill broke through into a space behind the cement facing of the wall, he forgot all else in his eagerness to find what lay there. He inserted a different blade in his drilling device, a cylindrical type saw, and cut horizontally and vertically, until he could lift a square section of cement out. Then his lips became grim with intensity.

For a sinister metal object rested inside. It was shaped almost like a small fire extinguisher. But it was painted a dull gray, and “X” knew that those strange looking gadgets on the top were for no such humane purpose as the extinguishing of flames.

This was an instrument of hideous destruction, placed there to kindle a holocaust of death and horror such as the city had never known. Its gray metal sides gave no inkling of the deadly stuff it contained. The nature of the new explosive element was unknown to Agent “X,” but the mechanics of radio-control were familiar. Such control had been used to guide battleships, airplanes, tanks and cars. Most of the governments of the earth were secretly experimenting with it. It would play a startling part if there came another war. “X” had studied many of the devices already perfected.

New and terrible as the detonating medium of this super-bomb was, the radio-impulse device was built along recognized lines. A few moments of investigation, as he held the terrible engine of death in his lap, convinced him of this.

He took out a small screwdriver, turned it slowly on the bomb’s head, knowing that if he made a slip it would spell oblivion for himself and a thousand others. But he made no slip. He removed two screws which permitted the dust-proof cover cap to slip off. Beneath this was the radio-impulse mechanism, the clockwork gear, already wound, to be set in motion by intermittent dots and dashes on a certain wave length.

With steady hands, calmly as though this were nothing more than an old alarm clock he was tinkering with, Secret Agent “X” took a bit of copper from his pocket, and with this wired the clockwork wheels so that they could not turn. The call of death might come now, unseen and sinister in the air. The Terror might try to bring this egg of doom to life, as he had the other — but this was one bomb that would not obey the invisible impulses.

Agent “X” quickly slipped the metal shell back into place, twisting the screws into it to hold it fast. And, as he did so, breath abruptly hissed through suddenly clenched teeth. His hands froze around the gray surface of the deadly bomb. The muscles of his body snapped into rigidity. His eyes flashed sidewise and remained fastened on the oblong of the door.

For, so intent had he been on not making a slip with the lethal bomb, that he had momentarily relaxed his vigilance, neglected to watch and listen. And now the door of the small wine cellar had darkened. Now four ugly, intent faces were framed in it — men of Gus Sanzoni’s gang. And in their hands were black automatics, the sinister, round muzzles pointing straight at the Secret Agent’s heart.

Chapter XIV

A SECOND of tense silence passed before one of the gangsters spoke.

“Stand up, guy — raise your mitts — and don’t go for a gat!” he said.

The gesture of a single gun muzzle emphasized the order. Agent “X” obeyed immediately. His hands went up above his head — but they were not empty. They carried the gray cylinder of the bomb with them.

A thin smile curved his lips. His flashing, penetrating eyes held a sardonic light. He remained quiet, staring at the four who had surprised him, and something about his manner held them taut.

The man who had given the order to lift his hands spoke again. “What in hell are you doin’ here? You must want a drink bad to steal from Gus Sanzoni! Put that bottle down — easy so you don’t break it — and come out. We’ll teach you it don’t pay to break into this joint.”

The Agent spoke quietly then. The sardonic hint was in his voice now. That, and his coolly precise speech, coming from the unkempt figure he presented, made the gangsters hunch forward.

“This isn’t a bottle I’m holding. Look again, pal, and see what you make of it!”

The man who seemed to be the leader of the group gave a growling exclamation. “Here, gimme that flash,” he said to a man beside him. He grabbed the proffered light, clicked it on and focused its beam on the thing “X” held. His hard, brutal face twisted into lines of puzzlement, and there was a shade of uneasiness in his eyes.

“What in blazes is it? Looks like an oxygen tank — the kind they use on guys that do flop acts at fires.”

The Agent’s laughter sounded then, humorless, harsh, seeming to mock his questioner. “Wrong again, pal. It isn’t an oxygen tank — and if you don’t watch yourselves and go easy you’ll all be blown to hell.”

Curses greeted this remark, and hoots of derision. “The guy’s nuts!” one gunman said. “Come on, boys, let’s give ’im the bum’s rush. T’row ’im out of here!”

“A dose of lead will fix ’im better,” said another.

The leader stood uncertainly, eyes focused on “X” and on that strange thing he held above his head. The Agent spoke again, driving home his point, for he saw that if they were not checked some move on the part of these men within the next few seconds might spell utter catastrophe.

“I’m handing it to you straight,” he said quietly, using language that they would understand. “This is a bomb I’ve got — a pineapple — but one of the hottest numbers you’ve ever seen. It’s the same kind that knocked Baldwin Island off the map this evening. But it’s twice as big.”

At mention of the explosion on Baldwin Island, fear came into the leader’s eyes. News of the thing had reached the underworld. The man spoke hoarsely.

“Lay off him, boys, he’s a nut all right; but maybe he’s telling the truth. We don’t want no trouble here.” He took several steps toward the Agent, his gun still centered upon him.

“Now, fella, hand over that pill you got and don’t make any fuss about it. You don’t want to get drilled even if you are cracked.”

The Agent gave a low chuckle of laughter again. The sound was as harshly abrupt as the crack of a whip.

“Turn that gun the other way! If you shoot — this bomb will drop. One bump — and there won’t be enough left of you or this building to scrape up. Stand clear — all of you — or you’ll get rubbed out.”

The Agent moved his right hand, made motions with his fingers close to the round top of the bomb. He seemed to be twisting a screw head.

“I’ll start the fuse,” he snapped, “if you don’t stand dear!”

One of the gangsters, a hophead judging by his chalk-white complexion, made a sudden whimpering sound.

“Geez! Lay off him! Leave the guy alone! A pal of mine was down by the river last night and seen the island go up in smoke. He told me about it — an’ if that’s the kind of apple that done it I don’t wanna fool wit it.”

AGENT “X” took the initiative. He moved forward with a menacing motion, and the gangsters stepped back. He was only partially bluffing. He couldn’t start the fuse by turning a screw, but, for all he knew, even a slight jar might serve to detonate it. He was using it as a means of escape, playing a deadly game with these hirelings of Sanzoni’s.

The leader spoke sharply to one of his men. “Go up and get the big boss,” he said. “Ask him to come down here. Tell him there’s a crazy guy threatening to blow the place up.”

They had backed out into the main part of the cellar now. They faced Agent “X” as he emerged from the wine room.

He saw that these men had no inkling of the truth. They didn’t know the nature of the protection that a master criminal had given their boss, Gus Sanzoni.

A moment later there was a creaking on the stairs, then a wheezing sound as the fat criminal, Gus Sanzoni, came down into the cellar. His small, piggish eyes were bright as he spoke in an unctuous, oily tone, thinking evidently that “X” was some half-mad criminal with a new sort of racket.

“Come on now, fella,” he said smoothly. “I’ll pay you big to take that thing outta here. You’re a smart fella, and I like smart guys. You’ve got a good racket, and I’m willing to come across. Just take that thing out easy, I got guests upstairs.” “X” intercepted a flashing signal from fat Sanzoni’s eyes. He saw two of the gangsters edging slowly nearer, ready to make a sudden lunge while Sanzoni talked. They thought “X” was some kind of a crazy terrorist. They planned to take the bomb away from him by guile.

“X” spoke again quickly, staring Sanzoni straight in the face. “No tricks,” he said harshly, “or none of you will live. This thing can’t be fooled with — and I didn’t bring it in. It was here already — and has been here for days. Look in your wine cellar. It was sealed in the wall there. I just took it out.”

More jeers came, but Gus Sanzoni looked startled.

“Go and see,” he wheezed. “You, José, find out if the guy’s telling the truth.”

A swarthy gangster detached himself from the group and disappeared into the wine cellar that “X” had so lately left. He came back big eyed, and nodded.

“It’s God’s truth, boss! There’s a hole in the wall — a place for that thing to roost in. The cement’s been cut away. That bomb must have been there — and this guy took it out.”

Sudden pastiness spread over Sanzoni’s fat face. His breath seemed to choke him, wheeze in his throat.

“Some one,” he gasped, “planted it there — to kill me!” he clenched his big hands, screamed sudden orders. “Search — you fools! There may be others!” His eyes glinted with cunning as he stared at “X.”

“You must be a detective,” he went on. “You must have got wind of the fact that that thing was there.”

There was a moment of silence, then the Agent answered slowly, each syllable falling dramatically from his lips.

“I am Secret Agent ‘X,’” he said.

He had reason for letting Gus Sanzoni and his men know who he was. He was gambling with death — staking his wits against the Grim Reaper, not to preserve his own life — but hoping to save the lives of others.

For he recalled vividly the words of the document found in Ballantine’s safe. “Any undercover attempt to thwart my plans will only result in catastrophe.” The Secret Agent had to think of those thousands who would be brought close to the brink of eternity when the Terror learned that some one was after him. If the Terror suspected the law was on his trail, he might make good his threat — send out the impulse that would plunge the city into the vortex of bloody horror.

But if he understood it wasn’t the law, but Secret Agent “X,” a man supposedly a desperate criminal like himself, and whom the police had many times tried to capture and imprison, he would take other means. He would try assuredly to kill the Agent as a dangerous rival. But he would see the uselessness of destroying the city’s thousands.

THAT was the Secret Agent’s mad gamble. Fear for once lay cold against his heart. Fear for the citizens who did not know their danger. Fear that he was playing too reckless a game. What if the Terror should suspect? But he could not think of that— He turned almost fiercely on Sanzoni.

The fat gangster’s jaw had dropped at mention of the dread name of Agent “X.” The eyes of his men had grown wide. Rumors, whispered along the byways of the underworld, had reached their ears. The pall of impenetrable mystery that lay over the Secret Agent’s activities made his character fearsome, awe-inspiring. That fear whitened the face of Sanzoni now. He obviously believed himself in the presence of an arch-criminal, pitiless, enigmatic, inhuman. He tried to speak, but only a wheeze came from his bloodless lips. One fat hand ineffectually pawed the air.

Agent “X” took advantage of the momentary sensation his disclosure had made. He made an abrupt movement, so quick that none in that room could follow it. His right hand, clutching the deadly bomb, swung down under his arm. His left snapped forward, the gas gun appearing as though by magic in his fingers — its muzzle pressed against the fat belly of Sanzoni.

“Now,” he snapped, “you will come with me! I want to talk to you — and if any of your men shoot or try to interfere, two things will happen. First, I’ll pull the trigger of this gun. Second, this bomb will drop — and blow you to pieces.”

Gus Sanzoni was quaking now. Prosperity had made him soft. Fear had a leechlike hold upon him. He found his voice at last.

“Keep away, boys,” he said weakly. “I’ll see what — what this man wants. Stand clear of the stairs.”

With Sanzoni mounting ahead of him, “X’s” gun at his back, the Agent guided the gangster from the cellar and took the bomb with him.

“Out that door,” he commanded. “Quick!”

With gangsters trailing them at a respectful distance, Agent “X” prodded Sanzoni along the dark street to his parked car. He took a roundabout route, away from the lighted entrance of the building.

“Get in,” he ordered when they reached the car.

For a moment Sanzoni hesitated. A jab of the gun made him jump. “X” threw the car into gear and shot away from the curb, the gun still in his hand. Driving swiftly through the night-shrouded streets, he turned and stared at the fat criminal. There was a look of flashing magnetic power in the Agent’s eyes now that evil-doers found hard to meet. Backed by the steady pressure of the gun, it menaced Gus Sanzoni, while the Agent asked a question.

“Who is the man who gives you protection, Sanzoni?”

The gangster’s lower jaw dropped. He swayed a little in the seat.

“I—” his breath came to a wheezing end. He began again. “I — can’t — tell — you!”

“No!” There was harsh derision in the Agent’s tone. “I’ll answer that question myself then. The mayor of this city hands it out. Isn’t that right?”

Another jab of the gun followed “X’s” words. The fat gangster’s silence and widening eyes gave mute confirmation to what “X” had said.

“And you’ve been pulling a lot of fast ones lately, Sanzoni,” went on the Agent. “Your men have been having it all their own way, without police interference. Who’s the fellow you divvy up with — that’s what I want to know? Come on, tell me, or I’ll pull the trigger of this gat — and dump you out in a ditch.”

This was the kind of talk Sanzoni understood. He had left riddled sodden corpses lying in ditches himself in his time. He saw violent death staring him in the face, and a trembling seized his body. He clenched and unclenched his fat hands.

“I–I don’t know,” he wheezed. “Honest, I never seen the guy. I just get orders — by telephone — where to leave the stuff. I leave it where he says. He’s got the mayor sewed up somehow. The bulls have been laying off my men like you say.”

The Agent’s face was masklike for a moment. An uncanny judge of human nature, he knew that Sanzoni was telling the truth. This was what he had half expected. This was what the document in Ballantine’s safe had led him to believe. Sanzoni himself didn’t know who the Terror was. “X” didn’t speak again. His purpose in forcing Sanzoni to come along with him had not been merely to question the man.

His gas gun flashed up now, quick as a striking snake. The Agent fired full into the fat gangster’s face, cutting off the scream that bubbled to Sanzoni’s lips. Sanzoni tumbled side-wise against the side of the car, inert as a bag of meal.

Making sure he was not being pursued, Agent “X” drove quickly to the same garage where a few hours before he had taken Bugs Gary. The ex-convict, formerly a Sanzoni man, was still his prisoner, in the house behind the garage. Now “X” carried the unconscious form of the gangster chief into the same house.

HE got out a hypo needle, gave Sanzoni an injection of anesthetic drug, which would insure his remaining out for at least twenty-four hours, unless the Agent chose to wake him with a counteracting stimulant.

Then “X” left the hideout, got into his car again, and drove away as swiftly as he had come. Time was a precious thing. Time — that Death might be held at bay.

Agent “X” looked down at the gray bomb now lying on the seat beside him. He was carrying one of death’s very germs through the night. He would take it somewhere, examine it carefully, make it yield whatever secrets it held. It might hold some clue to the Terror’s identity. It was a bet that must not be overlooked.

But in any examination there was danger that it might explode. For this reason he must take it far from the city’s teeming population, far from all human habitation. And speed was imperative. The Terror might try to bring things to some swift and ghastly climax.

Hunched over the wheel, knuckles white on its black rim, Agent “X” sped through the night. He had a definite objective now, a definite line of action.

He stopped at another hideout farther up town to make a quick change of disguise. When he emerged, he was no longer a nondescript, unshaven night prowler. He was a sandy-haired, blunt-featured young man, dressed in an ordinary business suit. He was A. J. Martin, newspaper man, connected with a large syndicate. But the deadly bomb lay on the auto seat beside him. The look of strained intensity still showed in the Agent’s eyes.

He raced along a wide avenue in the suburbs, drew up at last before a high iron gate with a broad field and low buildings beyond it. With the bomb under his arm, wrapped now in an old cloth, Agent “X” strode to the gate.

A sleepy watchman was on duty. He peered, nodded. “H’yer, Mr. Martin, gettin’ an early start this mornin’?”

The Agent merely grunted as he walked toward one of the airplane hangars. Far across the field, lights showed. A truck had come to a standstill. A fast, sturdy mail plane was getting ready to take off for the west.

SETTING the bomb down, Agent “X” unlocked and rolled back the hangar doors. He slipped into a teddy-bear flying suit which he took from a locker, adjusted a suede helmet on his head, slipped goggles over his forehead, ready to be snapped down.

Then he rolled out the small, compact plane that squatted in the hangar like some caged bird. It was swift, powerful, with the staggered wings, low camber and sweepback of any Army ship. It was the Secret Agent’s famous Blue Comet.

A mechanic shuffled out from the operations office; but Agent “X” had the bomb stowed away, the plane on the deadline and the motor warming before the man arrived.

Five minutes later he took off, sweeping up into the still black sky, carrying in the cockpit with him the metal cylinder that was the concentrated essence of Doom.

He climbed in short, swift spirals till the airport was far below, then headed the cowled nose of his plane northward, toward a lonely mountain field he knew. A rough log building stood there, with tools in it, and some laboratory equipment. Agent “X” had used it before to examine bombs and deadly gases. If any accident should occur, only one life would be wiped out — his own.

He planned to make a swift, thorough examination of the bomb, then return to battle with the Terror, perhaps with knowledge that would aid him in the one-sided fight.

But, with suburban lights still streaking below, some airman’s instinct warned “X” to look up. His goggled and helmeted head turned. He stared back along the plane’s sleek fuselage, and suddenly his hand tensed on the control stick.

A tiny, ghostly flame had appeared in the blackness above and to the rear. It was not a star; not a signal light on another ship. It was the feather of flame from the exhaust stack of a plane that he could not see. He closed his own throttle a moment, heard the whine of a racing motor.

Then a cry came from the Agent’s lips. For, as though the night had drawn itself together, into a vicious, mailed fist, something lashed down out of the blackness. Another flame sprang into sight now. It was greenish, flickering — and above the whine of the unseen motor he heard the staccato reports of a machine gun in action.

He knew in that instant that death was close. The other ship was above and behind. The silhouette of his Blue Comet could be seen against the ground lights. His own exhaust plume was visible also. And, with the crackling abruptness of a lightning bolt, the murderous attack came. Only the Agent’s quick thrust of the stick saved him from instant annihilation under the first deadly burst.

Bullets crackled through the Blue Comet’s orange wings. The Agent sideslipped away — but the brief, erratic flutter of the control in his hand conveyed a message of sinister warning. One of his ailerons had been struck. He was already crippled — with a murderer striking for his life.

Chapter XV

AT the moment “X” sensed his ship had been hit, he thought of the bomb. The deadly cylinder was tucked under his seat. It was wedged so as not to fall out — but any instant now it might explode.

If one of those ripping slugs so much as struck it a glancing blow, swift destruction would blast the night. Hours spent over war-torn fields in France years ago had taught Agent “X” all the tactics of aerial battle. As a youthful officer in Allied military intelligence, he had seen service on land, on sea and in the air. For the secret mysterious work of espionage knew no limitations, no frontiers. Only the picked few were chosen. Only the incredibly resourceful and daring survived.

The Agent did not attempt to dive away from that probing stream of lead. To do so would have been to court instant death. He drew the stick back into his lap, shot up in a screaming, hurtling zoom, with the thunderous power of the radial lifting his ship at elevator speed. Then he thrust the control to the left side of the pit as the plane came on its back, attempting a quick wing-over. But that crippled, damaged aileron played him false.

As though a giant steel cable had jerked it, the plane twisted around. It remained on its back, then side-slipped sickeningly. The next instant, as the attacking ship flashed by overhead, it threatened to go into a deadly flat spin.

Agent “X” eased it out gently, adjusting himself to the unequal aileron surface. For a moment the bullets were forgotten. His fight was with the treacherous unstable medium of the air itself — and with a ship that would not obey her controls.

Dread clutched at his heart, dread that he might plunge down into those populous suburbs. Human beings were sleeping down there. Men and women, children and little babies. If his plane, freighted with that sinister egg of death struck, peaceful well-cared-for homes would be transformed into charnel houses.

The killer above him was not considering that. In his savage desire to slay the being who was drawing close to his secrets, he was willing that hundreds of others should die. The Terror had said that his spies were ever watchful. One of them must have reported the theft of the bomb from Sanzoni’s headquarters. Perhaps he had men planted among the fat mobster’s own gang.

And now the attacking plane had turned, and leaden slugs were coming again. These were tracers. “X” could see their flaming paths. They testified to the flying murderer’s efficiency. And he was handling his guns like an accomplished air fighter. Could this be the Terror himself, or was it merely another hireling, a paid gunman of the air?

“X” did not know. White-lipped, blazing-eyed, he was fighting to hold death at bay. By piloting with the stick at an angle, using the full surface of the partially destroyed aileron to hold the wing up, he was accomplishing the seemingly impossible — flying level And this time he side-slipped away, letting the ship fall off on the good wing, and straightening out when the danger was momentarily passed. If he had not been crippled, he could have outflown and out-maneuvered this other pilot, though in sheer, straightaway speed, the attacking ship seemed as swift as the Blue Comet. In a moment Agent “X” saw why.

A screaming power dive carried the murder ship below him. He got a glimpse of its silhouette against a body of water, a suburban lake.

His airman’s eye identified it at once. It was a seaplane; stubby winged, unbelievably swift. Planes of this type were the fastest in existence, capable of speeds that won all records for velocity. Its twin pontoons were slim as knife blades. Its fuselage was streamlined like a torpedo. He was up against a terror of the air.

It came screaming up at him like some monster hornet with the bright lash of its sting playing an evil spray of fire. The other pilot planned to rake his underside now. That, too, was a fighting maneuver. Agent “X” had seen great German Gothas turned into flaming funeral pyres by the swift upward thrust of a pursuit ship, during the War.

He waited, seeming to hang on slack controls for an instant, then side-slipped again, as the bullets came close. Compared to him, the pilot of the attacking snip was a rank amateur — for all his masterly equipment. But the Agent’s shattered aileron was the hazard that made the outcome unpredictable. It seemed to be getting worse, as fabric and cracked metal worked loose.

For all his skilled touch on the controls, the Blue Comet was flying like a wounded bird. As he slipped this time, the ship would not straighten out immediately. And, when it did, its cowled nose dropped and it fell into a screaming spin that made black sky and lighted ground blend into a mad, dizzy jumble.

THE Agent fought desperately, sweat oozing out under the clamping curve of his helmet. Twice he stopped the corkscrew turns, sent the ship into a long glide, only to have it spin again. The third time he half rose in the cockpit, leaning far out over the padded coaming, adding his weight to the slender balance of the controls. The ship dived, leveled, and began a long climb.

Savagely, as though sensing that victory was close at hand, the other ship banked and came on. The Secret Agent pressed the Blue Comet’s throttle forward to the quadrant stop, gave the blasting cylinders of his radial the last drop of gas they could take. The pull drone of the steel prop as it bit into the air rose to a deafening scream. The slanted orange wings rocketed the plane skyward.

But the other ship still had the advantage of altitude. And its hurtling climb was equal to the Blue Comet’s. But Agent “X” had a plan. If the blind god of Chance favored him, if those raking bullets did not strike him or the bomb, he might yet escape the flying killer by reaching altitudes that the seaplane could not attain. For wing surface must count, given equal horsepower. And he believed his own wings were at least a foot broader.

Yet the hopelessness of his scheme was soon brought home. A steel-jacketed bullet glanced against a flat flying wire with a mocking spang. He presented too good a target. The man in the seaplane could not fly, but he could shoot. And the muzzles of his twin synchronized guns would accomplish what his hand on the controls might not. Those tracers made it too easy for him to point the nose of his ship at the crippled, helpless Blue Comet.

With a tug at his heart, Agent “X” made a swift decision. There was one last chance to save himself and the precious bomb — and to save those on the ground below from awful death. If he threw the bomb overboard, or left it in the plane with him dead or wounded at the controls — the result would be the same. An explosion that would surely wipe out other lives when the terrible engine of death struck. Yet if he sacrificed his plane, jumped now, taking the bomb with him — he might win his fearful game with death.

That was the final plan that Agent “X” had evolved. To make use of his seat-pack parachute, hold the bomb in a dizzy plunge earthward. To let the faithful Blue Comet crash pilotless, hoping that it would miss human habitation. Even if it struck, the disaster would not be as great as though the bomb were in it.

He braced the control stick with his knee, reached down and drew the gray cylinder from under his seat. Bullets slashed close around him, as though the fiend in the seaplane sensed some trickery, and was making desperately certain that his blood lust were not cheated. One of the crystal, gleaming dials on the Blue Comet’s instrument panel, a Sperry horizon indicator of latest design, smashed into a myriad needle-sharp particles that stung the Agent’s face. The engine gave a sobbing cough as a fuel gauge went next.

Bleak-eyed, holding the bomb beneath his right arm, his hand clamped around it, Agent “X” swung a leg over the ship’s side. Never had he so hated to sacrifice a piece of inanimate mechanism. The swift Blue Comet had been like a symbol of his power and vengeance over the black forces of crime. Its destruction seemed an omen of his own inescapable defeat. But if in sacrificing it he helped to bring about the Terror’s downfall, then the valiant ship would have been lost in a human and precious cause.

The weight of his body unbalanced the crippled plane. It turned, hurled him out — and the next instant Agent “X” was plunging earthward through the still dark sky.

One thing alone was fixed in his mind as his body dropped like a stone through space. The bomb! The deadly cylinder that his stiff arm and clawlike fingers clutched. He had made chute jumps before. The first, years ago over a field near Charlrois, when the high tide of the German advance was engulfing all Belgium in a red wave of fear. And when Agent “X,” as a brilliant Intelligence operative, was being dropped into enemy-held territory. Many other jumps had followed in the intervening years. But never had he gone overside with such an engine of death in his grasp.

He made a delayed jump now, did not pull the ripcord till he had fallen a thousand feet below the spot where he had left the Blue Comet’s cockpit. That was his only chance of escaping leaden death. For he knew the killer would not stop at blasting him from his ship. Guessing his daring maneuver perhaps, the man above, who knew no mercy, would try to complete his work.

Not till the ground with its sparkling lights came dangerously close did Agent “X” reach for the slender wire. Then he tugged it calmly, surely, and felt the harness jerk about his body blisteringly as the pilot chute leaped out and the big envelope of the chute itself blossomed.

His clutch on the bomb was vise-like. The strange silence of his slower descent was as though he had been whisked into another world. But, listening, he could hear the motor of the seaplane, and it seemed to him that the other ship had turned and was swooping down. The ground was only eight hundred feet below him. But he knew that in the next few minutes relentless death would be on his heels again.

Chapter XVI

IT came even before he had reckoned. The seaplane was in a power dive. His airman’s ears told him that. The ship was hurtling down out of the night straight toward his opened chute. The white spread of it must be faintly visible even in the darkness — presenting a perfect target.

He waited till the engine’s roar was echoing almost in his ears — waited till something zipped close beside him in the darkness. It was a tracer he knew. The acrid smell of the phosphorous was in his nostrils.

Then his left hand tugged at the parachute’s shroud lines. He gathered them in expertly, spilled air out of the great, white umbrella — and the chute fell off on that side, rocked dizzily and plunged a good hundred feet lower.

The seaplane came around in a snarling bank. He was surprised at the quickness of the maneuver. Its guns were chattering again as his fingers dug into the shrouds. The ground was only six hundred feet down now. The flying killer was desperate to get him. He heard a sound that brought a coldness to his heart. It was the spat of a bullet against the top of his chute. He looked up. A dull glow showed. An incendiary tracer had gone through the fabric, left a burning ring. Here was death in a new guise!

With hands taut as talons the Secret Agent gathered in the shrouds away from the side where the burning spot appeared. He tugged fiercely; let the big envelope sag away, hoping to blow the fire out. But the wind blast was not great enough. It only fanned the slow flame — and Agent “X” knew that he was poised on the very brink of eternity. The small, cankerlike flame festered in his chute. The ground five hundred feet below. The bomb under his arm — and the bullets of the killer above seeking to do still more damage. He must not drop too fast — lest the shock of landing set off the death cylinder he carried. Yet he could not risk another bullet in the fabric of his chute. One more, and the wind that spilled from the holes would increase his velocity to such an extent that the bomb would surely explode when he hit.

Now, before the greedy flame had grown too great, he must stake everything — win or lose.

The plane was coming for him, its guns chattering madly. It had swooped lower, its pilot anticipating another hundred-foot drop on the part of “X”. But the Agent gathered in the shroud lines now and clutched them tightly, cutting the chute’s surface in half, falling away crazily — pitching downward to what seemed inevitable destruction. But “X” was watching the ground, figuring his odds as calmly as though this were some pleasant outdoor sport he were indulging in.

The pilot of the death ship, thinking evidently that the chute had been destroyed, not supposing that any man would take such chances purposely, held his fire.

Night wind was sweeping the chute toward a lighted avenue. The slender lines of telegraph wires showed. A vacant field was beyond them, with dark shrubbery at its farther edge. There were houses all around, and lights were appearing in them, as sleepers, wakened by the machine-gun fire, got up to see what it was.

Agent “X” held his breath. He was falling at a terrible speed. The telegraph wires were directly below now. Tangled in them, he would not be able to retain his hold on the bomb. It would fall to the hard ground — and that would be the end, for himself and a hundred others in the suburban houses around.

He released the shroud lines then — played his last card, let the chute billow out again. For a second his speed was unabated — and wind whistled through the rent where the sullen phosphorous flame still burned. But the spread of the fabric was still great enough to act as a partial cushion. His calculation had been uncanny. His earthward velocity decreased. The wind carried him over the gleaming wires. The dark turf of the field beyond swept up.

And now “X” got ready for the greatest ordeal of all — the shock when he struck with the added weight of the bomb. He drew his legs up under him, bent his knees to act as springs, pressed the metal cylinder against his middle and doubled up over it, both arms around it as though it had been a football. And the next instant he hit!

It was a moment when all existence seemed to hang suspended; a nightmarish second that he was never to forget. For the wind pulled him off his balance, dragged him over the hard, frozen ground, and the shocks were like some malicious fiend striking out deliberately for the bomb.

“X” ROLLED over on his back, took the full force of the blows against his body, protecting the bomb with his own flesh. And, when the chute caught and stopped at last in the shrubbery at the field’s end, he lay dazed for a moment.

Then in the blackness above him he heard the sinister drone of the seaplane again. And it brought him to his senses like the voice of doom. He set the bomb down, drew a knife from his pocket and slashed himself free of the chute harness.

The next instant, as a dark shape hurtled down out of the night, he was sprinting toward the grove of trees, plunging in amongst greenbriar and dwarf cedars as bullets sought to destroy him.

But he knew he could not be seen now. He held the bomb safely, raced deeper into the woods, and the slashing stream of lead that clipped branches and spatted against the ground, swung away. Agent “X” was safe.

But he did not think of that. His desperate, daring work had made him slur over such contrasts. Safety — danger, came in too swift rotation. He only knew there was work to be done, an unheard-of menace to be battled. More than ever speed was imperative. For the Terror, learning how “X” had struggled to preserve the bomb, might suspect that he had some deeper motive than desire to chisel in on Gus Sanzoni’s racket. And it was apparent, from the air attack on “X,” that the Terror’s spies were everywhere; that he had secret knowledge of the underworld.

The Agent got out of his flying suit, wrapped it around the deadly cylinder. He paused suddenly. From far off there came a jarring crash — then silence.

That would be his faithful Blue Comet, passing to destruction. It was nothing but a tangled piece of wreckage now. He only hoped that no house or building had been in its path. He could not fly to his mountain laboratory in it. There wasn’t time to charter another ship. He was far from an air field.

He emerged from the woods, saw a small, suburban village ahead. It was late, long after midnight. The narrow streets were empty, the houses dark. But a few parked cars stood about, their owners too poor or too niggardly to rent garage space.

The Secret Agent moved quickly toward one. He could not dally with convention. In his battles with crime he used whatever means came to hand, when emergency pressed close. He would borrow a vehicle now, settle with its owner later if there was any loss. Those who unknowingly aided the Secret Agent always received double the value of the service rendered.

One of the cars was a common standard make. A key on the Agent’s ring, adjustable to any lock tumblers of a certain size, opened the door and started the ignition. In a moment he was driving away into the open country, with the deadly bomb beside him.

He located what appeared to be a deserted farm, judging by the condition of the buildings, and drove his borrowed car into an old barn. Here he turned up a box and laid the bomb on it.

Using the car’s headlights as laboratory lamps he spread out the compact portable tools that had been hidden in his pockets and strapped to his body during the chute jump. There were others that he would have liked to have but with these he had often before accomplished seeming miracles. There were files, a pair of clippers, screwdrivers, a hacksaw, and the goose-necked and pivoted bits of metal with which he opened locks. These would have to do in the strange task before him.

Quietly, calmly, he set to work, removing the bomb’s dust cap again, baring the intricate radio-impulse mechanism. A sudden horror filled him as he looked at it. What if the Terror should send out the fatal dots and dashes on a wave-length of nineteen meters just to blast him into eternity? This bomb would not explode, but eleven others might. He would be safe — but a whole city might be bathed in blood and death. For he had figured that all twelve of the hidden bombs must be sensitive to the same impulse.

His fingers trembled slightly as he began to disassemble the ghastly infernal machine. But soon they steadied. Here was work that called for the utmost care and caution. He located the bomb’s fuse and a tiny gunlike hammer which could be liberated by clockwork to descend on the detonating cap. He breathed easier when both had been removed.

He examined each piece that he took out, made brief but precise notes on a piece of paper. A micrometer gauge, accurate to the thousandth of an inch, gave him fractional measurements.

He viewed the inner casing of the bomb. It had been made to fit a thirty-seven millimeter shell, such as are used in the new aerial war cannon. The criminal genius who had devised the bomb had merely adapted it for a still more terrible use. And Agent “X” bent forward suddenly. For at the bottom of the case was a manufacturer’s mark, stamped into the metal.

The Agent focused a double-lensed magnifier upon it. It was the registered design of an American shell maker — the Schofield Arms Company, a small munitions concern which had prospered recently on orders for light arms and small caliber aerial cannon received from several Balkan States.

The mark itself did not excite “X.” He had seen it before during an investigation into the world munitions’ traffic, when he had collected data on the giant Skoda works, on the Vickers plants in England, and on a half dozen other European and United States concerns.

What did excite him was a fact stored away in his own memory. For he knew that the Schofield Arms Company was controlled by American interests, American investors, and foremost among them was a man the Agent had talked to only a few days before. This was Harrigan — member of the Bankers’ Club and close associate of Mayor Ballantine — who had gone out to interview Ballantine on Monte Sutton’s yacht, and had later been caught by “X” rifling the mayor’s safe.

Chapter XVII

EMOTION filled “X” as he continued his work. His startling discovery of the clue connecting Harrigan’s concern with the murder machine was like a whiplash spurring him on.

He removed the appalling explosive itself next. It was contained in a celluloid case. It was a greenish, greasy acid. The faint fumes coiling from it were like a miasma of death. He buried most of it under the barn floor where he could return for it later. He took out an infinitely small sample to be submitted to chemical analysis. And even these few grains, he knew, could reduce a man’s body to a bloody pulp.

He quickly reassembled the empty bomb, did it up again in his flying clothes, and left the deserted farm as he had come.

Grimly he drove through the darkness in the borrowed auto, headed back toward the city. There were still several hours of darkness left. There was much to be done in them.

In the next hour Agent “X” sent out commands to both of his undercover organizations. He commissioned Bates to investigate secretly the Schofield Arms Company and obtain all possible data as to their present activities in high-explosive manufacture. He asked Jim Hobart to locate Harrigan immediately.

Then Agent “X” went to the hideout where Bugs Gary and Gus Sanzoni were still unconscious prisoners. “X” had a move in mind more daring than any he had ordered Bates or Hobart to perform. It was a move that no other criminal investigator in the world would have thought of undertaking — a move that only Secret Agent “X,” Man of a Thousand Faces, was fitted to make, by talent and training.

He went to the couch at the side of the room where the gross, slumped figure of Gus Sanzoni lay. Every shade in the house had been drawn. Special, light-proof shutters of opaque boarding had been fitted by “X” on the inside of the windows in the chamber where he had deposited his prisoners. He switched on a small mercury vapor lamp now. Its beam made the room as bright as day. An achromatic globe over the lamp acted as a color-filter in bringing out the natural tints of Gus Sanzoni’s fat face.

Agent “X” studied the mobster intently. Sanzoni was breathing slowly and stertorously in his deep, drug-induced sleep. The Agent took a leatherette case of medicines and chemicals from a cabinet drawer. He tied a paper cone over Sanzoni’s face, let fall a trickle of blended ammonia spirits in a piece of cotton at the cone’s end. The fumes filled Sanzoni’s nostrils, entered his lungs.

Three minutes of involuntary inhaling, and Gus Sanzoni was breathing more quickly. His arms moved. His eyelids began to flutter. He had returned to the borderland of consciousness.

Agent “X” took a small bottle from the chemical case. It contained a colorless liquid — essence of sodium amythal. He poured a few drops of this into a whiskey glass of water, tipped back Sanzoni’s head, and made the man swallow.

Sanzoni’s movements and the fluttering of his eyelids soon ceased. He had come out of the influence of one anesthetic, only to be subjected to another. But this was of a different nature.

The Agent fired low-voiced questions at Sanzoni, and in a moment Sanzoni was giving reply. His answers were mere confused mutterings at first. But, as unconscious nerve centers took control, his voice grew stronger, became natural.

His answers were whining, suave, domineering — according to the questions “X” put to him. And these questions were seemingly unrelated to the criminal case in hand. They were questions concerning Sanzoni’s personal habits, his likes and dislikes in food and liquor, his attitude toward politics, his treatment of his men.

Other queries concerning Sanzoni’s communication with the Terror followed. “X” verified what Sanzoni had stated previously — that he alone was the one who dealt with the Terror’s representative, handing over the Terror’s share of the loot, after he had received a telephone call designating the place of delivery. “X” listened to Sanzoni’s voice as well as the words he uttered.

Several times he ordered Sanzoni to repeat a sentence. More than once Agent “X” spoke a phrase directly after the mobster. And the effect then was uncanny. For the Agent’s amazing power of mimicry made it appear as though two Gus Sanzonis had spoken. He mastered the gangster’s wheezing inflection, copied the involuntary gestures that Sanzoni made with his hands and arms as he talked.

And when he had gotten what he wanted, Agent “X” gave his prisoner still another administration of chemical — a hypo injection this time, of the same sort he had given Bugs Gary. Sanzoni returned to the realm of complete unconsciousness.

IT was then that Agent “X” began one of the most difficult disguises he had ever attempted. Sanzoni was the same height as himself. But there were those roils of fat on the gangster’s face and body to be coped with, the baggy flesh under his eyes, the flabby jowls.

These presented great difficulties. Yet Agent “X,” as a master impersonator, had anticipated that he would one day come up against such a problem. He had prepared.

In a locked, metal-bound chest in his hideout were sets of padding. Sets such as some great character actor might have possessed. These had been made for “X” by a famous Parisian stage costumer. He selected those which, fastened on, developed the rotundities of Sanzoni.

Then he began work on his own features, first stripping off his present disguise. With his volatile, quick-drying, plastic material he commenced molding the features of Gus Sanzoni upon himself. And here “X” employed the art of the sculptor. He could have done the same thing in clay. He had in the beginning of his strange career made countless experiments with plastic clay, till his powerful fingers had developed an uncanny quickness and accuracy.

Collodion formed one of the basic substances in the materials he used. There were others, known only to “X,” blended by a secret formula over which he had worked for months, till he had achieved just the right degrees of cohesiveness and mobility.

He modeled the flexed jowls of Sanzoni; duplicated the bags under the eyes, the thickened, flabby neck, the gross lips. And this padding of synthetic fleshlike material followed the movement of the real flesh beneath. When he smiled the sculptured features smiled also. When he scowled they moved in accordance with the muscular movement beneath. The principle of “X’s” disguises was no mystery. The only mystery was the lifelike effect his genius achieved.

For when he arose at last from before his triple-sided mirrors, the twin of Gus Sanzoni seemed to be in that room. And when he removed the gangster’s clothes and put them on himself, he seemed to be the real Sanzoni, and the snoring, sleeping man on the couch seemed to be his ghost. The padding over his own firm muscles filled the gangster’s oversized suit.

He practised Sanzoni’s walk across the room. He addressed the walls in Sanzoni’s wheezing, brutal voice. He stuck one of the gangsters cigars between his thickened lips, lighted it, breathed smoke and practised harsh gestures. He was Gus Sanzoni to the life.

But before he left his hideout he added two things to an otherwise perfect disguise. He discolored slightly the plastic material above his cheekbone to look like a bruise. Across his forehead he stuck a small strip of adhesive plaster which seemed to hide a cut. Even the cut was there, a reddish slit in the make-up, in case curious hands should remove the plaster.

TWENTY MINUTES later, a yellow cab drew up before the door of the Montmorency Club, and a man who would have passed anywhere for Gus Sanzoni stepped out. He seemed to be Sanzoni in one of his most evil moods. His heavy brutal features were twisted into a savage scowl. The frayed stub of an unlighted cigar projected from his lips. He flung a coin at the cab driver, turned and clumped sullenly into the club’s vestibule.

The doorman had gone off duty now. The last of the guests had finally left. The band had ceased playing. There was none to see Sanzoni’s apparent return till he mounted the red plush stairs and reached the floor of the club proper.

But the place was not as deserted as it seemed. A rat-faced gunman lounging outside the door of the club’s main room saw the lumbering form of Sanzoni, and gave a hoarse cry of excitement.

“Boss!” he said. “Boss!”

He thrust open the door behind him, called to those inside.

“It’s the boss, gents! He’s come back! He got away from that guy! He’s here.”

A score of silent, tense-faced gangsters were gathered in the room. Some had been leaning against the walls. Others sat glumly at tables with whisky glasses before them. Goldie La Mar, Sanzoni’s moll, looking old and strained, was pacing the room, smoking endless cigarettes. There was a stampede to meet the returning big shot.

Behind the disguise of Sanzoni, one of the most daring impersonations he had ever wrought, Secret Agent “X” was in a state of hair-trigger alertness. This was a challenge hurled into the face of Fate. This was courting death in death’s own stronghold. There was no bullet-proof vest beneath his clothing now. If he made a slip, if one of these men around him, or that nimble-witted woman, learned that he was not Sanzoni at all, but only a clever imposter, guns would blaze murderously. And the menace of the NP bombs would remain to imperil the city. Twice he had escaped close destruction in this building. A third time he had come to make the greatest gamble of all.

Goldie La Mar’s voice sounded above the rest, brittle, shrill with excitement. There was relief in her mascaraed eyes. Her painted lips curved in a dazzling smile. She had thought her meal ticket, her prestige in the underworld, had been snatched from her. Now they had returned in the person of Sanzoni.

She flung her powdered arms around Sanzoni’s neck.

“Gus!” she screeched. “Gus — we thought that mug had croaked you!”

Her cajoling, perfumed lips tried to cling to his. Agent “X,” with an irritable growl, playing the role of a man whose character he had sized up adroitly, flung her away. He made a wry grimace, clutched his shoulder, and winced as though in pain.

“Oh — he hurt you!” said Goldie La Mar. “You’ve got a cut — and a bruise on your face. How did you do it, Gus? How did you get away?”

Others flung questions at him. He was congratulated, admired, cheered. When he reached the inner room, a gangster shoved a glass of liquor toward him. Agent “X” tossed it off at a gulp; threw out his padded chest a little.

“That bird won’t bother us no more!” he said.

“How did you do it, Gus? Where is he?”

“Never mind. Pipe down — all you heels. And you, Goldie — it’s time you hit the hay. Clear out. Scram! I got business to attend to.”

Agent “X” walked on into Sanzoni’s private office. Four slinking gangsters, Sanzoni’s own personal bodyguard and lieutenants, detached themselves from the others and followed.

“X” heaved himself into Sanzoni’s chair, eyed these men who would have sought to kill him instantly had they guessed the truth.

“How did the work go?” he wheezed.

One of the men, a hatchet-faced, macabre-looking Sicilian, stepped nearer. He drew from his pocket a huge paper packet, laid it on Sanzoni’s desk. A half dozen other such packets followed until there was a pile of them.

“It went swell!” the gangster lieutenant said. “Those are all century notes. There are seven hundred of them — seventy grand, and that ain’t all.” He turned to one of his companions. “Cough up, José,” he snapped.

The second mobster disgorged packets of bills from his pockets. The pile on Sanzoni’s desk rose. The face of José cracked in a hideous smile.

“We t’ought you wasn’t comin’ back, boss — an’ we didn’t know w’at we’d do wid dis stuff. De vault opened easy, but we hadda knock off two guys to keep ’em quiet.”

“X” knew that here was more bank loot. Here was more evidence of the black wave of crime that still swamped the city — and would as long as the Terror held the threat of his dread “protection” over Mayor Ballantine’s head.

“X” nodded, drew the money toward him, and asked a sudden question.

“Any phone calls for me?”

The men looked at each other uneasily. The one who had first given him the money nodded and spoke.

“Yeah — a guy called you at two o’clock. But he didn’t say what he wanted. He sounded sore — because you wasn’t here. I said you’d be back later.”

Agent “X” didn’t reply. He lighted one of Sanzoni’s cigars, drew in smoke thoughtfully. But he was inwardly tense. Fingers of dread clutched at his heart. The man who had called had probably been the Terror, wanting to make arrangements for the delivery of his share of the money. Sanzoni had been out. He would not call again tonight, for the cold, gray fingers of the dawn were already stealing in through the window. Agent “X” made an impatient, sullen gesture.

“Scram, all of you. I gotta be alone to think.”

It was true; but not in the way they supposed. The gangsters withdrew and Agent “X” went to Sanzoni’s big safe. He did not know the combination. But, making sure the doors of his office were locked, he knelt before the safe, listened to the faint clicks of the lock mechanism, and easily opened the door. Inside were other packets of bills, and a small leather satchel — loot no doubt ready for delivery. The cash taken in the bank raid tonight formed an allotment, together with that in the safe. The Terror was impatient to receive his seventy per cent.

But Agent “X” could only wait now. He had made one of the greatest gambles of his life. He was like a man poised on the brink of some terrible inferno. Over those miles of city streets, through which the morning light was filtering, a pall of horror hung. There was a chance that thousands of the city’s citizens might never seen another dawn. He himself might not live to see it.

No saying how the Terror might respond to all that had happened. He had known about the Agent’s theft of the bomb. He would know also about Sanzoni’s capture by the Agent. He must have a spy in the Sanzoni gang. And “X” was depending now on the fact that the Terror would hear of Sanzoni’s return. His own statement that Agent “X” would bother him no more must surely reach the Terror’s ear. If it did there was hope. If it did not — death, the impulse that would set off the bombs, might come through the air that very day.

Chapter XVIII

IT seemed to Agent “X” that the hands of the clock moved with the maddening slowness of crawling maggots. His nerves were like crawling maggots also. He craved action, yet he must wait, wait! The lives of thousands depended on his caution, his cunning, now. He had entered into the role of Gus Sanzoni. He must make that disguise convincing till the purpose of it was achieved — till he made contact with the Terror, or the Terror’s messenger.

He went into the small, windowless den off Sanzoni’s office and pretended to sleep. But he wasn’t sleeping. His thoughts were active. He was planning his campaign.

The phone in Sanzoni’s office, he saw, was an extension. It would be suicidal to call Hobart on it. Other ears would listen in. The underworld was ever suspicious. Yet he must somehow get in touch with Hobart and Bates — learn whether Harrigan had been located and what Bates had uncovered. These details might influence his actions in the immediate future.

He had his lunch sent into his office, ate it somberly, and directly afterwards sauntered out a side exit of the club into the street. Two of Sanzoni’s bodyguards sought to accompany him. He waved them off growlingly.

“I got private business, see! After what happened last night I guess I can take care of myself. I don’t need you mugs now.”

There was a hint of suspicion in their blank faces. Agent “X” had an inspiration. He winked.

“You guys stay here and see that Goldie don’t follow. There’s a jane I gotta have a talk with — and it’s getting so I can’t move without Goldie tagging along.”

The gangster guards relaxed. This was a simple and understandable explanation of Sanzoni’s wish to go for a stroll alone. He had let them think there was another woman.

Agent “X” took a taxi, had the driver speed crosstown. He went into a drug store, called Jim Hobart. The excited voice of the redhead reached him at once.

“Boss, I’ve been expecting to hear from you all morning! That guy you asked me to locate, Harrigan — has disappeared! He’s left his apartment. He ain’t at his office. I can’t find any trace of him!”

A thin smile curved the Agent’s lips under the make-up of Gus Sanzoni. The man he suspected of being implicated somehow in the Terror’s activities had taken this time to drop out of sight. That might be mere coincidence, or it might not.

His voice snapped a response at Jim Hobart over the wire. “We’ve got to find him, understand, Jim! This is something big. You’ll know about it later. But keep after Harrigan, question his friends and servants. Find him. And when you do, send out a broadcast in the Z2 code. I may not have a chance to phone you again, but I’ll be listening.”

Agent “X” snapped up the receiver. Hobart would have been astounded, would have thought himself insane, if he could have seen the man he had just talked to — the man whose voice had been that of A. J. Martin.

Still in the role of fat Sanzoni, Agent “X” walked out of the drug store. He took another taxi to a different part of the city. Here he entered an apartment house where no gangster had ever visited. With a key he took from his pocket, not one of Sanzoni’s, but one which he had transferred from his own clothes when he dressed in the mobster’s outfit, he opened a door on the second floor. The place was empty, sparsely furnished. It was another hideout of Secret Agent “X.”

When the Agent came out he carried a cigar box with him. It was inoffensive. It would not attract suspicion. He had apparently visited a friend, and had been given a full box of choice Havanas.

WITH the box under his arm he hurried back to the Montmorency Club. Goldie La Mar had had her beauty sleep and was up for the day. She greeted him boisterously.

“Where you been, Gus? How you feelin’ after the fight last night? Ain’t you got a kiss for Goldie?”

She pouted her red lips at him, sidled up to him possessively. Agent “X” gestured her away. He screwed his face into a scowl, spoke gruffly.

“I’m busy, Goldie. I ain’t got time for no mushy stuff now!”

Hostility flared in the woman’s eyes. Yet he knew that if she wasn’t repulsed she would be a pest, interfering with his desperate plans. She snatched at his arm now. “Listen, Gus, you been actin’ funny lately.” For an instant it seemed to him that he read suspicion on her heavily rouged face. He spoke with swift calculation.

“Lay off me, Goldie! The boys say you got sweet with Bugs last night. You danced with him, didn’t you? You two-timing little—”

That brought pallor to her painted face. She shrank away. Her voice was husky, scared. “Gus — you don’t think—”

Agent “X” walked on, leaving the woman with something to worry about. His show of jealousy against Bugs Gary would keep her docile and quiet till she learned whether he was going to hold it against her.

In Gus Sanzoni’s office, “X” slumped into a chair again, laid the cigar box before him on the desk. He snapped open a little wire catch, raised the lid stealthily. Under the cover, at the top, was a row of cigars wrapped in tin foil. But the gleaming front they presented was only camouflage.

He lifted two of them, moved his fingers deftly on a small rheostat beneath. Finely made, watchlike mechanism filled the remainder of the box. It was a vest-pocket size radio receiving set, operating on two small, but super-powerful, dry batteries. Bending his head he could hear the faint dots and dashes of a secret code message. It was as though a tiny, shrill-winged insect were imprisoned in the box. Three feet away the sound would be inaudible. But Bates was broadcasting a report, and Agent “X” listened. There, in the stronghold of the Terror’s allies, he was getting a report from his own men.

A detailed account of the activities of the Schofield Arms Company came from the radio. Bates was a faithful, routine operative, who worked by rule of thumb and could always be depended upon to carry out an order. But his report now was not significant. The Agent changed the dial again, to the wave-length over which Hobart would signal in code Z2 if he succeeded in locating Harrigan. That had been “X’s” main motive in bringing the hidden radio here.

He was running a risk in doing it. If its presence were discovered, it would be his death warrant. But death was close, anyway. Somewhere the Terror was waiting for darkness, and the money that reposed in Sanzoni’s safe.

The afternoon dragged by. Dusk came at last, stealing across the city like some shadowy, sinister portent. Sanzoni’s men came and went; came for orders; came to tell their supposed chief about their murderous, criminal activities. “X” could not tell them to cease their raids. A few innocent citizens must still suffer — that death might not come to thousands. He must appear in all ways to be Sanzoni.

Sitting behind his desk, he gave directions to Sanzoni’s evil horde — and waited for the call that would be a command for Sanzoni himself.

Yet the cigar-box radio on the desk before him was silent. Hobart had not succeeded in finding Harrigan. The Agent’s campaign against appalling, ruthless crime still hung in doubt.

He got up at last, paced the private office, looked at the lighted streets of the city. Men and women were hurrying by, unaware of the danger that threatened every instant. Others, laughing, elaborately dressed, would come here to the Montmorency Club, to dance and be gay, while doom crept close.

Goldie La Mar stuck her head in once. Meek, blonde and perfumed, clad in a clinging green evening gown, she spoke in sugary tones.

“Ain’t you gonna have no dinner, Gus? I had the chef fix up all the things you like. I wouldn’ta danced with Bugs last night — only he asked me to — an’ I wanted to find out what he had to say for himself.”

AGENT “X” waved the woman away. “Don’t bother me, Goldie. I’ll eat when I’m ready.”

He had his dinner brought into his office again. He nibbled at it, had the dishes taken away, and sat hunched over the desk, apparently in deep thought, but really listening for the insect note of the concealed radio.

Then at ten o’clock the telephone beside him rang abruptly. The Agent was conscious of a slight trembling of his hands as he lifted the receiver. It might be one of a score of people calling the gangster chief, some underworld acquaintance of Sanzoni. But a secret hunch told him that it was not. Personal calls had been few and far between all day. The club’s acting manager, a suave-faced young mobster, took care of the routine business.

“Gus Sanzoni, speaking,” he wheezed. And as soon as the voice sounded at the other end of the wire, the Agent’s body tensed. For the tones of the voice were flat, unemotional, and spoken in a peculiarly measured way. Agent “X,” a close student of phonetics, knew that the voice he was hearing now was disguised; knew that it was spoken by a man who did not want his identity revealed — the Terror.

“You were not at hand to receive my second call last night,” the voice said. “Why?”

“I–I had to leave!” the Agent wheezed. “I was taken away — by a guy who called himself Secret Agent ‘X.’”

There was an instant’s pause at the opposite end of the wire. Then the disguised voice came again. “And this man — Secret Agent ‘X’—where is he now? What did he want of you?”

Recalling the air battle over the bomb, “X” knew that he must not make the slightest inconsistent statement.

“I croaked him, chief,” he said. “I had to — he wanted to chisel in on our racket. He gave me a shot of dope — knocked me out for a couple of hours. I don’t know where he went then. When I came to I was in his apartment, but before I could get on my feet again, I heard him coming back. So I laid low. He thought I was still knocked out — then I jumped him. We had a fight — and I slugged him proper. Then I came back here. He had a bomb planted in the cellar. He’s a bad guy — but he won’t bother us no more. A coffin’s the only thing he’s got any use for now.”

The Agent’s knuckles were white on the black receiver of the phone. He was playing a bluff that brought sweat to his forehead — sweat, because he feared for the lives of those teeming thousands outside. His voice sank, became more of a wheeze.

“I’m sorry I wasn’t here last night, chief, when you called. But I got some stuff — nearly a hundred and fifty grand. A hundred for you — all in cash.”

“Take a cab to the foot of Smith Street,” the order came. “Get out, walk across the vacant lot at the right. Stand in the shadow of the big billboard. My man will meet you at ten o’clock. That is all.”

The mention of the hundred thousand in cash had done the trick — diverted the Terror’s mind from Agent “X.” Not suspecting for an instant that any man would attempt such a thing as the impersonation of Gus Sanzoni, he had accepted the Agent’s story about his own death. It was now half past nine. In ten minutes Agent “X” would go forth to meet the henchman of the Terror.

Chapter XIX

HANDS clenched tightly, eyes bleak, Agent “X” started to rise from Gus Sanzoni’s desk. Then he stopped. Out of the wooden cigar box before him a faint, insect-like buzz was issuing.

“X” darted a glance toward the door, saw that it was closed and bent down. He recognized at once the dot-dash signals of the Z2 code. This was a special, syllabic code he had worked out with Jim Hobart, forcing the lanky redhead to learn it in many a tedious session with a telegraph key and a buzzer. Picked up by any amateur or commercial operator, its groupings would be unintelligible.

But the message was brief and plain, simple as day to the Secret Agent’s trained ears.

“Harrigan located. Visitor on Sutton’s yacht Osprey. Is expected to remain there as guest until yacht sails on cruise for southern waters.”

Patiently, in precise dots and dashes, Jim Hobart began the message again. But Agent “X” lifted the lid of the cigar box and clicked the current off. If any one came in and walked close to the desk, that insect buzz would be a betrayal — and he had heard all he needed to know. Harrigan was on the Osprey—probably with the mayor again. Previous reports had informed “X” that Mayor Ballantine was spending a great deal of his spare time on the yacht.

Agent “X” gathered up his cigar-box radio. He walked with it to the black safe in the corner. He again opened the safe, without listening to the lock now, for he had memorized the combination. He took out the black satchel, carefully counted out one hundred thousand dollars, and tucked them away in the satchel’s bottom. This left room at the top for his secret radio. He did not want to leave it behind him here.

He closed the safe, put on Sanzoni’s hat and coat, and, with the satchel in his hand, he left the Montmorency Club by the side exit again. Several of Sanzoni’s gangsters saw him. But he didn’t speak, and they made no attempt to follow as a bodyguard. This was proof to “X” that they were accustomed to Sanzoni’s nocturnal departures, with the Terror’s share of the loot. Perhaps they did not know what Sanzbni carried in that satchel. But he had evidently impressed them with the fact that he was to be left alone when he went out with it at night.

“X” followed the Terror’s instructions, took a cab to the foot of Smith Street, a dark commercial thoroughfare that led toward the black waters of the river. Its shops and warehouses were closed now. The cab jolted over rough cobblestones. The driver looked nervously about him when the vehicle stopped.

Agent “X” paid the man, struck off to the right, where he saw the dark expanse of a vacant lot. In the shadow beside a big warehouse loading platform, he drew the cigar-box radio from the satchel. He stooped for an instant, thrust the radio through a broken board under the platform itself. Later, if he chose, he could retrieve it.

There was not a soul in sight. The vacant lot seemed a place of desolation, of possible death. If this were a trap, the Terror could have found a no more likely spot. A thin, vicious cat rattled stones as it slunk out of “X’s” path. For a moment its green eyes glared back at “X.” This was the only indication of life.

He saw the big billboard the Terror had mentioned rising on the far side of the lot. Its surface showed a ghostly white in the darkness where a faint wash of street light reflected.

Agent “X” picked his way across the lot, every sense alert. He knew it must be close to ten. The Terror’s man must be near at hand, somewhere in the darkness. His own figure must be silhouetted by the glow in the street beyond. This was part of the Terror’s plan, so that his representative could be sure Sanzoni had come alone.

When the billboard rose directly above him, Agent “X” paused. All around him the darkness was complete. The great bulk of an old factory building rose on his left now, shutting out all light from that direction. Beside him was the smoke-blackened framework of the billboard. A thin streamer of dank mist off the river raced by him in the gloom like a hurrying specter. He heard no sound of footsteps, no indication of human presence.

But, as a great clock in a square blocks away boomed the hour of ten, a voice spoke beside the Agent:

“Give us that satchel, mister.”

A SMALL, wiry man, sure-footed and quick as a rat, came out from the skeleton maze of the billboard supports. Without waiting for “X” to reply, his fingers closed over the satchel. He took it and whisked away as quickly as he had come. It was all over in an instant. The Agent had met the Terror’s man — and the Terror’s man had gone.

But there were grim lights in Agent “X’s” eyes. He had come here for a purpose. That purpose was not to be lost sight of.

He picked his way quickly back across the vacant lot. At Smith Street, he turned right toward the river. Suddenly he sped through the darkness like a silent, racing ghoul. His quick brain had been working. The rat-faced man had come from behind the billboard, come from the side facing the water. There was a dark street of deserted stores and few lights at that point, with old wharves to hide on, and innumerable doorways in which to crouch. It was there surely that the Terror’s man had gone.

Agent “X” stopped short when he reached it. His rubber-soled shoes had made no noise. His eyes had adjusted themselves to the dim light. There had been rumors that Agent “X” could see in the dark. This was not so; but he had trained himself to make use of any available light beam; of illumination so dim that the average person could have seen nothing.

He did not miss the faint movement a half block away which marked the passing of the rat-faced man. He even got the man’s direction — and he followed with the cautious footsteps of a master shadower.

From doorway to doorway he slunk. Crouching at times, creeping Indian fashion across open spaces that he must traverse, eyes never losing sight of the man ahead.

The Terror’s henchman looked back once. He could see nothing. His actions indicated that he felt himself safe. Often before he must have met Sanzoni, picked up the loot, and carried it to his master. He had no reason to believe tonight that the man who had come as Sanzoni was any other.

And the course he was taking was parallel with the waterfront.

Agent “X” crept closer, using the opposite side of the street. Dock entrances afforded shadowed shelter here, as did also the parked trucks, silent and still for the night. The Agent was almost opposite the small man now. He paused suddenly as the Terror’s representative left the sidewalk, crossed the street, and moved along the river’s edge. The man plunged between two covered docks, disappeared for a moment. But Agent “X” was soon at the mouth of the alleylike passage that led directly to the river.

He saw that the rat-faced man had snapped on a flashlight. He was bobbing along toward the black water, the satchel in his hand. The beam of the flash was lighting the ground ahead of him, and abruptly Agent “X” crouched forward, eyes narrowed.

For the thrusting beam of the electric flash had centered on a boat. It was a small boat, painted white. There was faint lettering on its bow.

As the man stooped intently, loosening a mooring rope and arranging his oars, Agent “X,” crouched to the ground, coming closer. He held his breath as he made out the name that the letters on the boat’s bow spelled. There were six of them, forming a single word. That word was familiar to Agent “X”—Osprey.

JIM HOBART’S message flashed through his mind at the same instant as he saw it. Harrigan had been located. Harrigan was on the Osprey. And now the Terror’s man, with a hundred thousand in stolen bills, was using the Osprey’s boat.

The Agent could have leaped out of the darkness and made a prisoner of the man. But, so close to his goal, he dared not take chances. There was no saying what the Terror might do if his messenger from Sanzoni did not arrive.

The Agent waited in the darkness, saw the rat-faced man shove off onto the black, sucking tide of the river, heard the faint rattle of the oarlocks as the boat drew away.

He was holding his breath, tense in every muscle. But he turned and sped back to the riverfront street. In a black patch of shadow he tore at his face, peeling off the awkward make-up of Gus Sanzoni. He substituted, from tubes of plastic material that he carried, one of his “stock disguises” that he could fashion by the sensitive touch of his fingers alone.

He drew the padding that had made him bulky as Sanzoni from beneath his clothes. The suit, many sizes too large for him now, hung slackly on his muscular frame. It was not comfortable, it even impeded his movements; but he could not help it.

“X” had prepared for different kinds of water travel from a variety of hidden bases. There was a spot at the river’s edge where an old barge had sprung a leak and sunk. The water was shallow. The forward part of the barge was still above the surface. The company owning it had not cared to go to the expense of salvaging it, or having it destroyed. It had been roped off, left to rot. There was a gaping hole in its side where ice cakes in winter storms had battered in the planking.

Agent “X” leaped to the barge’s deck from a near-by dock. In a moment he was above the jagged hole in its side. Hanging by his hands he lowered himself, angled his body beneath the deck, and disappeared from sight.

Two minutes passed, and the knife-sharp bow of a small, odd craft appeared. It was a featherweight, Eskimo type kayak — a slender boat made of canvas stretched over a wooden framework. Agent “X” sat in the middle, in a circular cockpit. A thin, double-bladed paddle propelled the craft. Outside of a racing shell, it was the fastest type of one-man boat in the world.

He pushed it from beneath the barge where he had kept it hidden, sent it skimming out onto the river. Swift and silent as a surface swimming seal, he drove it along with expert sweeps of the paddle, rocking from side to side as he dug the blade in.

He paused to listen. The faint squeak of oarlocks reached his keen ears. That would be the Terror’s man, rowing toward the Osprey. Cutting down his own speed, Agent “X” followed the sound. He could have overtaken the other, reached the Osprey ahead of him. They traveled parallel with the city, continued nearly a mile up the river, to the yacht club opposite which the Osprey was anchored.

Agent “X” saw the Osprey’s lighted portholes at last. He started, straining his eyes in the gloom as he came nearer. A feather of smoke showed above the Osprey’s single funnel. The boat was getting steam up, preparing for departure it seemed, and Harrigan, the man connected with the Schofield Arms Company, from which the inner casing of the radio bomb had come, planned to be among the guests on the contemplated southern cruise.

Agent “X” heard a faint rattle as the unseen rower shipped his oars. He drew cautiously closer, and saw a porthole, near the waterline, darken for a moment. Either the Terror’s man had slipped through that, or some one had reached out to take the satchel from him.

Grimly Agent “X” approached the yacht. He circled it once. Faint strains of music reached him. Monte Sutton was having a party again. Men and women were dancing, drinking, laughing, not knowing how close to the black mystery of death they were. For if the stolen loot was taken to the Osprey the man who called himself the Terror could not be far off.

Agent “X” saw the row boat tender swinging at the end of the painter. The tide had pulled it out behind the anchored yacht. The rat-faced man had gone aboard. The lee side was the place for “X” to land. But a sailor was patrolling the deck above. Coming close, Agent “X” could see the man’s outline against the painted woodwork of the boat. Clad in pea-jacket and knitted cap, the man was dressed against the December chill. He was stationed on regulation watch.

The Secret Agent maneuvered the sharp nose of his kayak close. He edged silently along the yacht’s side, pulses hammering. Then he stopped, shipped his paddle carefully. He grasped the end of a thin silk painter in his teeth, and swung up the vessel’s side, using the ports as toe and hand holds. In a moment he stood on the yacht’s deck, and made his slender painter fast to the boat’s brass railing, using an expert seaman’s knot.

But as he raised his head, a low voice called a sharp command. The next instant the patrolling sailor leaped toward him, and in the man’s hand was the gleaming outline of a gun.

Chapter XX

AGENT “X” stood quietly as the man approached. He did not attempt to run. Did not speak. His attitude was deceptively careless. He slouched against the railing.

But, when the sailor was close, gun thrust menacingly forward, eyes peering at “X”, the Agent ducked and plunged forward. So lightning quick was he, that the sailor was unprepared. A chopping uppercut of the Agent’s left hand sent the gun spinning over the rail into the water. The Agent’s right fist connected with the man’s jaw with a swift, clean crack that made the sailor sway on his feet, then collapse groggily to the deck. He rolled over, lay inertly, completely out.

Agent “X” stooped, shoved his unconscious body into the shadows by a coil of rope. Then the Agent glanced up at the yacht’s funnel again. The smoke told him that the boilers were being fired. The oil-burning furnaces must be heating fast. Steam was almost up. It was nearly eleven now. Perhaps the yacht was to leave at midnight as many liners did. And it could not, must not, leave, with the Terror upon it.

The Agent acted quickly. The time for a showdown had come. He was convinced that all the stolen loot, collected in a score of murderous robberies, was somewhere below decks. He was certain that the Terror was on board.

He turned and raced silently along the deck toward the nearest entrance-way. Through a lighted window he got a glimpse into the main saloon. The dancing couples were there again. Agent “X” bent forward intently. He saw many people that he recognized. There was the puffy, troubled face of Mayor Ballantine. There was the tall grim form of Police Commissioner Foster. There, too, was Harrigan, immaculate in evening clothes, with Monte Sutton beside him, and a black-haired laughing girl on his arm.

There were many from the city’s wealthy, political set. This was evidently a farewell party. Ballantine himself possibly was among the traveling guests.

Agent “X” studied Harrigan’s face. The munitions man looked white, strained. There were furtive shadows in his eyes. The smile that came to his lips at something his girl companion said was mechanical.

Agent “X” slipped on, passed the lighted saloon, until he came to another entrance. Here he listened for seconds, then opened the door, and entered upon a carpeted passageway inside the luxurious yacht. Familiar with all types of ship design, he made his way forward, surely, swiftly. Any instant he might meet someone — a guest, or one of the yacht’s crew. There was no possible explanation he could make. He must count on quiet, secrecy, or a quick, knockout blow if he were caught.

He passed the doors of a half dozen luxurious staterooms. Voices issued from one. He listened a moment, went on; then he came to the door he sought. Behind this was obviously the yacht’s wireless room. It was in the forward part of the ship. But there was no sound from inside, no spark in attendance at the moment. The Agent opened the door cautiously to make sure, slipped inside.

He switched on the light, shut the door behind him. There was no bolt. He propped a chair under the doorknob, turned his attention to the radio set. It was modern, complex, complete in every detail; but it offered no problem to the Agent. Radio engineering was one of the subjects he had delved into profoundly.

This was the ship’s radio for long-distance sending and receiving. It had keys for the sending of code, a microphone for voice broadcasting. Glittering dials and tubes were mounted on a huge black panel.

FOOTSTEPS sounded in the corridor outside as the Agent stared about. Some one passed the door. Any instant he might be interrupted. The message that he had to send was imperative. He and his staff of organized investigators had worked for days outside the law. Now it was time for the law to be summoned.

And he had the means to do it. Bates had been instructed to listen for messages from his employer. He would be prepared to receive one now, wherever he might be, because he carried on his person one of the Agent’s vest-pocket receiving sets.

With deft, experienced movements. Agent “X” switched in the transmitting apparatus, started a generator whirring, saw a bright spark leap across the gaps. He turned down to the short wave-length that would reach Bates, and began tapping the rubber-topped key, sending out the dots and dashes of the secret 26G code. If Hobart should pick up this, it would mean nothing to him. It was for Bates’ ears alone.

“Get in touch with police,” tapped “X”. “Have harbor patrol surround and board steam yacht Osprey. Daring criminal and many thousands in loot on board. Speed imperative. Boat leaving soon.”

He repeated the message again and again, fingers moving mechanically on the keys, eyes wandering curiously about the room. There was a panel on the side of the wall which he had not at first noticed. He reached up, opened this with his left hand. Inside was a cabinet, filled with more radio mechanism. Squat tubes with silvered caps gleamed in a Bakelite base. Odd-type condensers were visible. A coil of black wire, some sort of a power unit, rose in the center. In front of the whole thing was a metal grille, locked at the bottom.

Agent “X” bent forward tensely, his hand leaving the key of the transmitting set, cutting off Bates’ message. And at that instant, as Agent “X” stared aghast at the interior of this mysterious cabinet, the mechanism of which carried a message to his scientifically trained mind, the door of the radio room was thrust inward.

In one and the same movement Agent “X” slammed shut the panel he had opened and whirled to face the door. The top of the chair slipped off the knob. The door swung inward, and “X” saw the faces of two startled sailors framed in the entrance.

He did not give them time to think or question him. He plunged toward them, yanking his gas gun from his pocket. One went down, but the other ducked, shouted — and almost instantly three men in the uniforms of ship’s officers appeared. Monte Sutton’s boat was well-manned. Agent “X” plunged into the corridor and saw that he was trapped.

Two stewards were coming along the passage from the rear. The three ship’s officers offered a barrier in the other direction. The sailor who had dodged his gas jet, leaped toward him with a furious cry — Agent “X” crouched, lashed out with his fist. The sailor’s quick feint showed that he was a boxer. He ducked again, flung himself at “X,” hammering in with short-arm blows. They clinched, and Agent “X” swung the man bodily, heaved him forward to crash into the opposite wall.

But five others were on top of him now, and far down the passage he heard the hoarse shouts of the guests rising in a bedlam of sound. Agent “X” went down in the carpeted passage under a crashing weight of human bodies. Using a wrestler’s technique, he squirmed out from under, got a scissors grip on the biggest of the yacht’s officers, and twisted the man on his back. Then something cold and hard was shoved against his neck. A voice shouted in his ear.

“Lay off, feller. Quiet there — or you’ll get a bullet in your brain.”

The cold thing was the muzzle of a gun. Agent “X” arose slowly. The officer that he had squeezed with the crushing scissors hold lay on the carpet breathless and groaning. The second man seized his arm. The third, still holding the gun against his neck, issued another order.

“Walk forward. No funny business — or you’re a dead man!”

Agent “X” was shoved along the passage toward the saloon where the guests were assembled. The orchestra had stopped playing. A tense silence reigned in the big cabin. White, excited faces were turned toward “X” and the officers who held him. The Agent presented a strange figure in the baggy, ill-fitting suit of Sanzoni, hanging loosely now on his powerful frame. His last make-up had been a hasty one. He looked like a tough and dangerous young man.

“We caught this chap aboard, sir,” said one of the officers, addressing Sutton. “He’s a bad-actor — and almost killed Jarvis.”

“Where was he?”

“In the radio room, sir.”

MONTE SUTTON swore under his breath. The guests looked startled. Police Commissioner Foster came forward and buttonholed “X,” taking the authority of the law into his own hands.

“Now,” he growled. “What’s the meaning of this? Who are you?”

Agent “X” did not answer at once. He stared from face to face. Harrigan was standing a short distance away, eyes intent and strained. Mayor Ballantine was watching him closely.

“There’s a criminal on board this yacht,” “X” said quietly. “You’re in the right place, commissioner.” He looked hard at Mayor Ballantine. “Some of you,” he went on, “may have heard of a man who calls himself the Terror.”

The Mayor gave a hoarse gasp. His face twitched. Harrigan turned paler. Commissioner Foster shook “X’s” arm roughly.

“What are you talking about? Are you crazy?”

“No — not crazy, commissioner! You know that a crime wave has disgraced the city, that the police have been ordered to lie low, and that millions have been stolen. What if I should tell you that the loot or most of it is on this boat?”

Monte Sutton spoke then. “This man must be mad. Take him away, men! Lock him up till we can get him on shore.”

Agent “X” fixed his gaze on the yachtsman. Craft was in Sutton’s eyes now. His face was hard, lined.

“Wait!” said “X” harshly. “You have an interesting radio room, Sutton! I might ask you to explain several things I found there — but I already understand—”

A transformation came over the face of Sutton. The mask of the dapper society man fell away. He appeared all at once predatory, criminal, vicious. He crouched forward, fingers crooked.

“So—”

Agent “X’s” voice rose. “I came to this yacht shadowing a man who carried a hundred thousand in stolen cash. He used the Osprey’s tender. He came on board the Osprey. Now I know who the Terror is. First clues pointed to another man. He is now on board the yacht. What do you know about this, Harrigan?”

Commissioner Foster broke in angrily. “Radio the police, Sutton. This man’s a raving maniac.”

“No,” said Mayor Ballantine suddenly. “I don’t know who he is, but he seems to know a lot. I—” He stopped speaking, gave a gasp, for Monte Sutton, dapper yachtsman, had given a sudden signal that the officers of his yacht seemed to understand. They backed away, faces hard. One slipped through a doorway, out on deck. Sutton addressed his guests, staring at Mayor Ballantine.

“So!” he said again, “you decided to disobey the Terror’s warning, Ballantine, and you, too, Foster!”

Agent “X” understood that Sutton thought he was a spy, hired by the mayor and his commissioner of police.

Words that were like a scream rose to the mayor’s throat. “Good God! You, Sutton — you are the Terror! You planted the bombs!”

Chapter XXI

THE mayor’s words had an electrifying effect on the guests assembled in the cabin.

“Bombs!” a woman cried hysterically. “What does he mean?”

“Take me on shore!” another whimpered. “Take me away from here!”

Monte Sutton laughed harshly then. His gesturing fingers swept toward “X”.

“This man, this detective of yours, Foster — let him tell my guests about those bombs! Or, no — I will. It’s true, my friends, there are bombs — but you will be safer here than ashore. The city is to be blown up presently. You will have a nice view of it from here.” Sutton laughed again. His eyes blazed with fury. “I am the Terror!” he cried. “And I am a man of my word! I made a bargain with Ballantine and Foster. They didn’t keep it. Let them and others pay the price!”

A BREATHLESS silence followed his words. Then the mayor spoke in a shaken voice. “No, Sutton! God, no! You can’t do it! This man wasn’t hired by us!”

“You lie!” screamed Sutton. “You tipped him off to come here. And now you’ll see what you’ve done!” He shouted another order at one of his officers. “Get underway! Quick — damn you! We sail at once.” When the man had gone, Sutton turned back to his guests, his eyes brutally mocking.

“Harrigan can tell you as much about these bombs as I,” he sneered. “The explosive in them came from his company. It was he who told me about it in the first place.”

The munitions man made a choking sound in his throat. His face twitched.

“You dirty thief, Sutton!” His trembling hand gestured toward the others. “I hold controlling interests in the Schofield Arms Company. They’ve been experimenting with a new explosive for months — keeping it dark. It’s the most violent thing of its kind in the world — and it was stolen mysteriously a few weeks ago. All our efforts to trace it failed — and now I understand why. I was a fool to mention it to any one — even my supposed friends. But I did — and Sutton was among them! Criminals hired by him made the theft, of course. I half suspected some one was using the explosive to force the hand of the city administration. I even went to the mayor’s house and opened the safe like a common burglar in the hopes of finding some evidence. But I didn’t guess for an instant that Sutton—” Harrigan’s voice trailed away despairingly.

Agent “X,” listening, felt a coldness around his heart. Sutton, he knew, was drunk with a sense of his own power — mixed with fury that his plot had been uncovered before he was ready. Now he was on the point of blowing up the city. The yacht was already moving. These men on board, in spite of their dapper uniforms, were criminals, too. Sutton’s next words showed his determination to make good his hideous threat.

“In a few minutes,” he jeered, “only a few minutes — and all of you will see what those bombs can do!”

Agent “X” spoke slowly, dramatically, a strange smile on his face as he put up a desperate bluff.

“I wouldn’t explode them if I were you, Sutton! You may remember that one of the bombs was found. I brought that bomb to the yacht with me. If the others go up — you and your yacht will be blown to hell!”

Sutton turned incredulous eyes on the Agent. He came close and shook a finger in “X’s” face. “A lie — another lie! You don’t know anything about that bomb! The man who found it is dead. You never saw it. You couldn’t even describe it if your life depended on it.”

“No?” His eyes fixed on Sutton, the strange smile still twitching his lips, Agent “X” told calmly of the finding of the bomb. He gave a description of the radio mechanism, told in detail how the bomb looked and how it worked. And when he finished, Monte Sutton was white and shaken. He gave another fierce order to an officer who was standing by.

“You hear what this man says? Look all over the ship — find that bomb!” As he spoke, the windows of the saloon were raised. Sailors standing on the deck outside shoved gun muzzles through, covering every man and woman in the cabin.

“You’re all my prisoners,” said Sutton. “You, too, Foster, head of your damned police — as well as this spy you sent here. If he’s not lying we’ll find that bomb — and then—”

“You won’t get away with it!” Foster shouted. “You’ll go to the chair for this, Sutton!”

Sutton, laughing like a demon, walked up and struck the commissioner in the face. Then he turned to Agent “X.”

“You will die,” he said gloatingly, “but not until you’ve watched the city go up. It won’t be a pretty sight — but it will be something to remember — the grandest fireworks you’ll ever see. I—”

He paused suddenly, whirled toward a window. As the yacht moved ahead, something sounded in the darkness outside. It was a moaning wail, like the voice of the night protesting. It rose in pitch — became identifiable as the siren of a boat. Other sirens took up the cry abruptly. They were all around on the black water. The harbor patrol had arrived.

Monte Sutton staggered back. The commissioner of police gave a cry of amazement mixed with intense satisfaction.

At that instant “X” saw the man who called himself the Terror leap toward the wall and press a button that plunged the saloon in darkness. He saw Sutton turn and dash toward the passage at the cabin’s end. And he got a glimpse of the man’s face in a stabbing searchlight from one of the patrol craft sweeping up. Sutton’s features were convulsed. He was in the grip of stark emotion, a raging, unholy devil of a man, lips skinned back from his teeth, fingers clenched.

And in that instant Agent “X” divined Sutton’s intent. A cry of horror came from his own lips. Sutton had been defeated in his plot. Yet there was one last coup he could make — a coup that brought beads of sweat to the Secret Agent’s forehead. If this happened, his own efforts, his desperate struggles, would have been futile.

He sprang across the cabin after the black shadow of Sutton. All about him was confusion. Men and women were crying in excitement. The sirens of the police boats wailed. The sound of shots as Sutton’s criminal crew tried to fight off the law. But in the Agent’s mind was no confusion — only cold purpose.

He reached the door of the passageway through which the ship’s officers had shoved him a few minutes before. He saw Sutton’s figure ahead, a furious streak at the end of the passage. The corridor curved, following the deck line of the boat. “X” lost sight of Sutton for an instant. When he rounded the bend, the man ahead had just hurled himself through the radio-room door.

AGENT “X” after him. The door slammed in his face. He beat against it. Bullets, fired by the human demon inside, ripped through the wood, plucked at the Agent’s coat.

Ignoring them, risking his own life that horror might not come to thousands, Agent “X” flung his full weight against the door. It crashed inward; but Sutton was already bent over the instruments in the covered cabinet. A motor-generator was whirring somewhere. Sutton had the metal grille unlocked.

He was reaching for a button inside, fingers taut as talons, eyes gleaming. The man was going to blow up the city anyway, risk the explosion of the bomb that Agent “X” claimed to have brought with him — and commit suicide rather than give himself up to the law.

A gun in Sutton’s left hand streaked up. Agent “X” dodged aside as the muzzle lanced flame. Sutton screamed a curse at him, tried to press the gun against his body. Agent “X” battered the gun down and clamped viselike fingers over Sutton’s right hand, snatching it away from the radio signal button. Then he crashed into Sutton, knocked the man to the floor.

Sutton was a kicking, clawing, biting fury. His frenzy gave him amazing strength. He tried to sink his teeth into the Agent’s arm, reached up with gouging fingers to press out his eyes. The Agent struck with desperate, sledge-hammer blows. His knuckles found Sutton’s chin, snapped the man’s head back. With a sigh and a groan Sutton relaxed, and flopped back on the floor.

But Agent “X” was taking no chances of his coming to before the police found him. He stooped for an instant, pressed a small hypo needle into the man’s arm. That would keep him in a stupor for several hours.

Then “X” went expertly through the man’s pockets. In one he found a small-scale city map. His eyes gleamed at this. Red marks showed on it — a dozen of them. Here were the locations of the hidden bombs. One of the marks, at the block of the Montmorency Club, was proof of that. Now the police bomb squad could find them. Harrigan would tell them how to handle the NP bombs. The Agent’s work was done.

He stooped down, pinned the map to the front of Sutton’s coat, left it on the inert figure. And with it, he left brief penciled instructions to the police, urging that they round up Sanzoni and Sanzoni’s gang for the part they’d played in the crime wave. He listed the mobsters’ names, added the names of several witnesses. Bugs Gary had done nothing and could go free when he recovered consciousness. But “X” would dump Sanzoni on a certain street corner where the law would find him.

The Agent went to the door then, listened, and stepped out into the corridor. The sounds of shots were diminishing now. The police had overcome criminal resistance. They were boarding the yacht. Soon Sutton’s criminals, and Sutton’s share of the loot, would be in the hands of the law, too.

No one saw the human shadow that moved out on the yacht’s side deck. Crouched and silent in his rubber-soled shoes, Agent “X” slunk across the deck, and down the side of the craft as he had come. The dark and drifting kayak in the water had escaped attention. It looked more like a floating log than a boat.

Agent “X” paused a moment as he stepped into it. Commissioner Foster had come out of the saloon. He was talking to a grizzled captain of the harbor patrol who had boarded the yacht. The captain spoke harshly.

“It’s lucky we got your orders, commissioner! This tub’s speedy. It would have been out of the harbor in another twenty minutes.”

“Orders!” said Foster in amazement.

“Yeah. They telephoned down to our dock from headquarters — said you’d sent a radio out from the yacht here. We got here as fast as we could. Now let’s find that loot.”

Commissioner Foster did not answer. His face was a mask of wonder and surprise that he took pains to hide. But the Agent’s kayak slipped away silently, moved across the black river — and then out of the darkness came a strange whistle. It was eerie, melodious, like the call of some wild night bird — the strange, unforgettable whistle of Secret Agent “X”—man of Mystery and Destiny.