Hui Ping sat bolt upright on the lab stool, dropping a screwdriver on the table with a clatter, as Crane crept into the lab.
"God!" she said. "You practically scared me to death."
"Sorry."
"You took so long. What happened?"
"I just had to return a few messages, back in my stateroom." Crane didn't bother to mention the ten-minute questioning he'd just endured on his way back through the Barrier: two marines who were very eager to discover the location of Dr. Ping. There was no point making her more nervous than she already was.
"How are you coming?" he asked, stepping forward and placing his laptop on the table.
Hui was laboring over a complex contraption that, to Crane's untrained eye, appeared to be several lab instruments joined by a forest of ribbon cables. In response to his question, she pushed herself away from the table.
"Just finished the last test."
"Looks like rocket science to me."
"It is rocket science. Almost. A magnetometer, chained to an A/D converter, and both in turn slaved to a timecode striper. The whole thing's capable of making a bit-by-bit copy of Dr. Asher's erased hard drive."
Crane whistled. "Trust Asher to fit his labs up properly. What if you didn't have all these cool toys?"
"The magnetometer is vital. I could do without the rest, but it would take a lot longer." She reached for his laptop, then paused. "I'm going to have to wipe your hard drive. Sure you don't mind?"
Crane shrugged. "Go ahead. All my files are on the network, anyway."
Hui booted up his laptop and typed in a series of commands. "This may take a few minutes."
A silence settled over the lab while the hard drive trundled.
"While retrieving my laptop, I did some thinking," Crane said at last. "Whoever degaussed Asher's computer wanted to make ultra sure what Asher discovered remained a secret."
"I was thinking the same thing. But that person also didn't want anybody to know he was trashing it."
"Precisely my point. Otherwise they could have simply taken a sledgehammer to the laptop."
"But who? And why?"
"The saboteur?" Crane said.
"Seems unlikely, doesn't it? I don't know his motives, but if I was the saboteur, I'd want that data for myself." Hui stood up.
"My money's on Korolis," Crane said.
"Why's that?"
"As far as I can tell, he lied about your presence at Outer Hull Receiving and in the hyperbaric suite." He hesitated. "Does your resumé mention that internship at the data recovery facility?"
Hui nodded.
"So he knows about that, too. I don't think he wants anybody learning what's on this laptop."
"I hope you're wrong. He'd make a very dangerous enemy." Hui stood up. "We're set."
Removing the case from his laptop, she attached the end of a ribbon cable to the hard drive, leaving the power cables connected. Then she powered up the chain of devices, made a few adjustments, and simultaneously engaged switches on the magnetometer and the digital timecode device. A low whirring filled the lab.
"How long will this take?" Crane asked.
"Not long. Apparently, Dr. Asher was like you-he did most of his work via dumb terminal on the Facility's mainframe. I doubt the laptop holds more than his personal e-mail, Internet files, and the work on the codes."
Ten minutes went by in which little was said. Hui monitored the extraction process while Crane puttered around the lab, picking up instruments and replacing them, trying not to grow impatient. At last the whirring noise stopped.
"That's it." Hui turned off the devices, removed the ribbon cable, placed the case back on Crane's laptop. She turned toward him. "Your hard drive should now be a replica of Asher's. Ready?"
"Fire it up."
She pressed the power button and they both crowded around, watching the screen. For a moment, it remained black. Then there was a brief chirp and the OS splash screen appeared.
"Bingo," Hui said softly.
Crane waited as she loaded a file management utility from one of her CDs and began exploring Asher's documents.
"Everything appears to be intact," she said. "No data dropouts."
"What's there?"
"It's as I suspected. E-mail, a few scientific articles in progress. And then a large folder titled 'decrypt.'"
"Take a look at that."
Hui typed a series of commands. "It contains several utilities I'm not familiar with-probably language translators or decryption routines. There are three subdirectories, as well. One called 'initial,' another called 'source,' and a third called 'target.'"
"Let's see what's in 'initial.'"
Hui moved her mouse over the icon. "It contains just one file, 'initial.txt.' Let me bring it up." She clicked the mouse and text window opened.
"Judging by the length," she said, "I'll bet it's the very first signal the platform workers discovered, the high-frequency seismic ping. The one that led us here in the first place."
"You mean, the one transmitted from beneath the Moho."
"That's right. Dr. Asher doesn't seem to have made an attempt to decipher it."
"He was concentrating on the signals the sentinels were transmitting. They were shorter, easier to work with. And my guess is they're located in the 'source' subfolder."
"Let's check." A brief pause. "Looks like you're right. There are about forty files here, much shorter."
"So Asher and Marris only parsed forty of the signals for decryption. What do you want to bet the other subfolder holds the translations?" Crane felt his excitement grow.
"I wouldn't take that bet. Let's check the contents." Hui moused over the screen. A new folder opened, containing a list of the contents of "target":
1_trans.txt
2_trans.txt
3_trans.txt
4_trans.txt
5_trans.txt
6_trans.txt
7_trans.txt
8_trans.txt
"There they are," Hui said, her voice almost a whisper.
"So Asher and Marris had translated eight of the forty messages when they called me. Hurry, open the first one."
Hui moused over the icon, clicked. A new text window opened, containing a single line:
x = 1/0
"Wait a minute," Crane said. "There's something wrong here. That's Asher's old, original translation. The one he got wrong."
"I'll say he got it wrong. Anybody who could build something as complex as those sentinels must know you can't divide by zero."
"He told me the decryption had gone so smoothly at first they figured they'd made some tiny mistake. So they wasted days trying to figure what they did wrong. When they went into the hyperbaric chamber, they'd given up on that and were taking a new direction entirely." Crane frowned at the screen. "This is old news. There must be another folder somewhere."
There was a pause while Hui consulted her file utility. "Nope. This is the only viable folder."
"Take a look at the second file, then. Maybe he just didn't bother to erase his wrong guess."
Hui opened "2_trans.txt":
x = 0 0
"Zero to the power of zero?" Crane said. "That's just as undefined as division by zero."
Another thought struck him. "Can you check the time and date stamp on those files?"
A few clicks of the mouse. "Yesterday afternoon."
"All of them?"
"Yes."
"That was when he was inside the chamber, all right. So they are new, after all."
Crane lapsed into silence while Hui opened the six other files. Again and again, they were simple mathematical expressions; again and again, they were illogical, impossible.
a 3 + b 3 = c 3
x = a/b
x = In (0)
"A cubed, plus b cubed, equals c cubed?" Hui shook her head. "There are no three numbers that will satisfy that expression."
"Or how about the natural logarithm of zero? Impossible. And pi is a transcendental number. You can't define it by dividing one number into another."
"And yet it seems Dr. Asher was right the first time. About the translations, I mean."
"He clearly thought he was. But it makes no sense. Why would those sentinels be broadcasting a series of impossible mathematical expressions? And why would they consider them so important they'd be transmitting on every known frequency…and then some? I think that-"
Crane abruptly fell silent. From outside in the corridor he could hear muffled conversation, the sound of tramping feet.
He turned toward Hui. She looked back, eyes wide.
He pointed toward the back of the room. "Into that closet. Quickly."
She ran to the equipment closet and slipped inside. Crane turned off the lights with a quick slap of his palm, then followed as quickly and silently as he could. At the last minute he stopped, stepped back out of the closet and into the room, and plucked the fire-suppressant drop cloth from its hook.
The footsteps came closer.
Crane spread the drop cloth as evenly as he could over the laptops and equipment on the table. Then he raced to the closet and shut them both in. A moment later, he heard the lab door open.
He peered out of the grille in the closet door. Two marines stood in the entrance of the lab, silhouetted by the glow of the corridor.
One of them snapped on the lights. Crane leaned back into the darkness. He could feel Hui's warm, rapid breath on his neck.
Footsteps again as the marines stepped into the room. Then silence.
Slowly-very slowly-Crane leaned forward again, until he could just peer through the grille. He saw the marines standing by the lab table, doing a slow recon of the room.
"There's nobody here," one said. "Let's try the next lab."
"In a minute," the other replied. "I want to check something out first." And-with cautious deliberation-the man stepped toward the closet.