The last book was located in a place more difficult to get to. Niccolo Polo had managed to conceal it high on the front facade of the mosque of Haghia Sofia itself, above the great curved arch that stood before the principal dome of the former basilica.
Ezio chose to complete his mission in the wee hours before dawn, as then there would be the smallest number of people about. He reached the building unchallenged and carefully made his way to the exonarthex, looking up at the cliff of stone he had to climb. There were few crevices for his hookblade to get a grip, but after several unsuccessful attempts, he managed to climb to the spot Sofia had pinpointed. There, he found a weathered wooden panel, overhung with cobwebs.
He managed to belay himself to some nearby pipework which, after testing it, he found solid enough to take his weight, and he used the hookblade again to pry the panel open. The wooden board fell away, falling to the ground beneath with what to Ezio’s ears was a deafening, echoing clatter, and he hung there in the grey light of false dawn silently, praying that no one had been alerted by the noise. But after he had waited for three whole minutes, and there was no reaction, he reached into the cavity the board had concealed and from it drew the book he sought.
Once back on the ground, he sped away and found a quiet spot in the very park where he had dined with Sofia only the day before, and there examined his find. The book was a copy of Luitpold of Cremona’s Mission to Constantinople. He allowed himself to imagine for a moment Sofia’s pleasure at the sight of such a rarity, before turning to its front.
The blank pages glowed about as brightly as the thin streaks of dawnlight he could see away to the east across the Bosphorus. And a map of the city appeared, which, as he watched hopefully, resolved itself into focus, and on it appeared another light, brighter than the rest, clearly marking the Forum of the Ox.
Following the trail indicated in the book, Ezio made his way to the Forum, away in the west of the city, past the Second and Third Hills, and about midway between the Aqueduct of Valens to the north and the Harbor of Theodosius to the south. It was quite a walk, but when he arrived, it was still too early for anyone to be about. Ezio scanned the huge, deserted square for some kind of clue, but the marked spot in the book gleamed sharply, and he remembered the system of subterranean cisterns beneath the city. He concentrated his search and located, after a little time, a manhole, from which stone steps descended into the bowels of the earth.
Ezio closed the book and stowed it safely in his satchel. He replaced his hookblade with his pistol, checked his hidden-blade, and warily made his way downward.
He soon found himself in a vaulted cavern, on a stone embankment by which an underground river ran. Lit torches stood in sconces on the walls, and, as he crept quietly through a narrow, damp corridor, he heard, above the sound of rushing water, voices echoing, raised above the din the river made. Following the sound of them, he came upon two Byzantine Templars.
“What have you found?” one said. “Another key?”
“A door of some kind,” his comrade answered. “Bricked up with hard stone.”
Edging closer, rounding a corner, Ezio saw a number of soldiers a short distance away, standing on an old pier that jutted into the river. One of them was rolling a barrel off one of two waiting rafts.
“That sounds promising,” the first of the nearer Templars said. “The first key was found behind a similar door.”
“Is that so? And how did they open that door?”
“They didn’t. The earthquake did.”
On a signal from the men closer to Ezio, the other soldiers came up with the barrel, which they proceeded to lodge in place against the door. Ezio could now see that the opening was sealed with close-fitting blocks of some hard black stone, cut by a master mason.
“The earthquake! That was helpful,” said the second Templar. “And all we have is a few barrels of gunpowder.”
“This one should be big enough for the job,” replied the first.
Ezio’s eyes narrowed. He quietly released his gun and pulled back the hammer.
“If it isn’t, we’ll just get more,” the first Templar continued.
Ezio raised his arm and took aim, but the barrel of the gun caught the light of a torch as he did so and glinted, the unusual flash of light catching the eye of one of the soldiers.
“What?” he snapped.
He saw the gun and leapt in front of the barrel at the same moment that Ezio fired. The ball struck him, and he fell dead instantly.
Ezio swore to himself.
But the soldiers were onto him.
“It’s the Assassin! Let’s get out of here!”
Ezio tried to reload, but the soldiers were already making their way back toward the rafts. He followed them, desperate to stop them before they could raise the alarm. But as he reached the pier, they were already pushing off. By the time Ezio had leapt onto the second raft and was struggling to loose its moorings, the soldiers were in midstream, floating away.
He had cast off and was in pursuit when the thought struck him-were they scared of him, or were they leading him on? Well, it was too late now. He’d have to play this to the end.
As his raft was lighter, the current began to carry him closer. The soldiers seemed to be in a panic, but that didn’t stop them from priming bombs and loading muskets.
“We have gunpowder aboard, we should use it!” one cried.
“We’ll blast him out of the water,” said another, throwing a bomb, which exploded as it hit the water barely a foot ahead of Ezio’s prow.
“Give me some room,” yelled another soldier, trying to steady himself to take aim with his musket.
“Shoot him!”
“What do you think I’m trying to do?”
“Just kill the bastard!”
They careered on downstream. Ezio had managed by then to grasp the tiller of his raft and bring it under control, all the while having to duck and dive to avoid the musket balls that cannoned toward him, though the pitch and roll of their raft made it all but impossible for the soldiers to take serious aim. Then one of the barrels aboard worked free of its ropes and rolled around the deck, knocking two soldiers into the torrent-one of them their tillerman. The raft bucked wildly, throwing another man into the black water, then smashed into the side of the embankment. The survivors scrambled to the bank. Ezio looked up to the high vault, which ran perhaps twenty feet above the river. In the gloom, he could see that a taut rope had been slung the length of the roof, and no doubt barges or rafts were often hooked to it to guide them down the river. You’d only need one person aboard with a pole to unhook and rehook round each of the eyelets to which the rope was affixed at regular intervals.
And Ezio could see that the rope, following the river’s downhill course, sloped gradually downward, too. Just enough for what he had planned.
Bracing himself, Ezio steered his own raft for the embankment, and as it smashed into the one he’d been pursuing, he leapt from it onto the stone pathway at the river’s side.
By that time, the surviving soldiers were already some way ahead of him, running for their lives-or to summon reinforcements. Ezio had no time to waste.
Working fast, he swapped his gun for his hookblade, scrambled up the side wall of the cavern, and threw himself toward the rope over the river. He had just enough momentum to catch it with his hookblade, and soon he was shooting downstream over the water, far faster than the soldiers could run though he had to unhook and rehook with split-second timing at each eyelet in the roof to avoid falling into the roaring torrent beneath.
As he caught up with the soldiers, he reversed his first maneuver and unhooked at the crucial moment, throwing his body sideways so that he landed on the embankment just ahead of the Templars. They stopped dead, panting, facing him.
“He is a madman,” said the first Templar.
“This is no man-this is a demon,” a second cried.
“Let’s see if demons bleed,” bellowed a braver comrade, coming at Ezio, his sword whirling in his hand.
Ezio performed a hook-and-roll over his back and pitched him, while he was still off balance, into the river. Three soldiers remained. The fight had all but gone out of them, but Ezio knew he could not afford to be merciful. The ensuing clash was short and bloody, and left Ezio nursing a gashed left arm; and three corpses lay before him.
Gulping air, he made his way back to the sealed door. They had come a long way downriver, and it took him a good ten minutes to regain the jetty where the rafts had originally been moored. But at least he knew that he need be in no immediate fear of pursuit; and the barrel of gunpowder was still lodged where the Templar soldiers had placed it.
Replacing his hookblade with his pistol once more, Ezio loaded it, chose a position upstream, from where he could take cover behind a projecting buttress, took careful aim, and fired.
There was the crack of the pistol and the hiss of the ball as it shot toward the barrel, even the thud as it struck home, but then there was, for what seemed an eternity, silence.
Nothing happened.
But then…
The explosion in those confines was like a thunderclap, and Ezio was deafened, thinking, as tiny stones rained down all around him, that he might have brought the roof in, that he might have irreparably damaged whatever was behind the door. But when the dust settled, he could see that for all the force of the explosion, the sealed entrance was still only partially breached.
Enough, however, for him to look within it and see the familiar plinth, on which, to his intense relief, the circular obsidian key, partner to the others he had collected, rested undamaged. But he had no time to relax. Even as he reached for it, he noticed, emanating from it, the glow that he had experienced with the others. As it grew in intensity, he tried, this time, to resist its power. He felt undermined, unsettled by the strange visions that succeeded the blinding light he had come to expect.
But it was no use, and he felt himself once more surrendering to a power far greater than his own.