“What do you mean?”

“The Janissaries have raised the chain across the mouth of the Golden Horn and ordered a full blockade until you are caught.” Yusuf paused. “Until that chain is down, nothing sails in or out.”

Ezio felt rather proud. “You mean they raised the chain for me?”

Yusuf was amused. “We will celebrate later. Here—I have something for you.”

Drawing Ezio into a discreet alcove, he produced a bomb and carefully handed it over. “Treat this with respect. It has fifty times the kick of our usual bombs.”

“Thank you. And you had better gather your people. This will attract some attention.”

“Here are two smoke bombs. You may find them useful, too.”

“Bene. I know what to do.”

“I’m sure. The suspense is palpable,” joked Yusuf.

“I’ll take the tower on the south bank. It’s closer.”

“I’ll join you at the quay and point your ship out to you. Sinav icin iyi sanslar!”

Ezio grinned. “Good luck to you, too, my friend.”

Yusuf was about to go when Ezio stopped him.

“Yusuf, wait. Un favore.”

“Yes?”

“There is a woman running a bookshop at the old Polo trading post . . . Sofia. Look out for her. She is a remarkable lady.”

Yusuf gave him a keen look, then said, seriously. “You have my word.”

“Thank you. And now—we have work to do.”

“The sooner the better!”

Placing the bomb carefully in his side pouch, and hooking the smoke bombs onto his belt, Ezio swapped his left-hand hidden-blade for his pistol and immediately hastened north toward the tower opposite Galata, on the south side of the Horn. The great chain was suspended between the two banks.

There, Yusuf joined him. “My archers are in place. They’ll cover your escape,” he said. “Now—look—there, in the outer harbor. The red dhow with the furled white sail and the silver pennant? That is Piri’s ship. It is crewed and ready. He is waiting for you.”

There was an open area around the tower, surrounded by ramparts and two smaller watchtowers from the tops of which taut haulage ropes led down to jetties and the western and eastern extremities of the area. At the outer point of one of them, Ezio noticed a weapon emplacement. A massive squitatoria, a flamethrower for Greek fire, stood primed, heated, and ready for action, manned by a crew of three.

Around the tower itself stood a number of Ottoman guards. Ezio would have to put all of them out of commission before he’d be able to place the bomb, and he thanked Yusuf silently for the smoke bombs. There was nowhere to take cover, so he moved in boldly and quickly for a frontal attack.

As soon as the guards saw him, a hue and cry was raised, and they massed to fall on him. He stood his ground, letting them approach but drawing his scarf closely over his nose and mouth and pulling his hood low over his eyes.

As soon as they were within range, he pulled the pins on both bombs and threw them to the right and left among the guards. They detonated instantly, and dense grey smoke billowed out, encompassing the guards in a moment. Diving into the confusion, Ezio, eyes narrowed against the acrid fumes, drew his scimitar and with it cut down all the defenseless soldiers as they staggered about, disoriented by the unexpected fog that suddenly surrounded them. He had to act quickly, for the light wind blowing in from the Bosphorus would soon disperse the smoke, but he succeeded, and placed the bomb on a ledge at the base of the tower, just beneath the first huge links of the chain, which rose above his head to the winch room inside. Then he took a good few steps back toward the water’s edge and from there unleashed his pistol and fired at the bomb, igniting it, then instantly diving for cover behind a large iron bollard on the quay.

The explosion was immense. Grime and stones were thrown everywhere as the colossal chains snapped free of the tower and whiplashed over Ezio’s head into the water, snapping ships’ masts as they flew past. As Ezio watched, the tower itself shifted on its base. It shifted again, seeming to settle; but then it imploded, collapsing in a mass of broken brick and dust.

Moments later, a platoon of Janissaries rushed into the square, heading straight for Ezio, who by then had broken cover. He dodged past them and used his hookblade to scale the eastern watchtower, knocking out the guard at its top when he reached it and hooking himself to the rope leading from it down to the jetty on which the squitatoria was placed. As he prepared to effect a zipline, he saw the Janissaries fitting arrows to their bows, but before they had time to take aim and fire, they themselves were cut down by a hail of arrows that rained down on them from Assassin bows. More Assassins rushed into the area around the ruined tower, skipping lightly over the debris to engage with the Janissaries who’d survived the first onslaught.

Among them was Yusuf. Looking up, he yelled to Ezio, “Remember—the red dhow! And the ships between you and it are armed—they’ll stop you from sailing if they can.”

“I’ll take care of them,” Ezio called back, grimly.

“And we’ll clear the docks!”

Ezio let the rope take his weight on the hookblade and kicked off from the watchtower, zooming down to the flamethrower emplacement and leaping off just before he reached it, throwing himself at the nearest of the crew, who were preparing to turn their weapon on the Assassins fighting by the tower. The first he knocked into the water, where the man was crushed between the shifting hulls of two moored barges. The others he swiftly dispatched with his hookblade.

He scanned the flamethrower, quickly acquainting himself with its mechanism. It was on a swivel base, operated by a crank at the left-hand side. The cannon itself was made of brass, its mouth in the shape of a lion’s head, from which the end of the bronze tube within projected slightly. On its edge it was a flint that could be sparked by the trigger mechanism, which also released the pressurized oil vapor that would be shot from the heated vat in the base of the weapon.

He heard a voice coming to him from the melee near the broken tower. It was Yusuf. “That’s it! Get the ships with Greek fire,” he was yelling. “I like the way you think, Ezio!”

Across the Horn, on the north bank, the Ottoman Guard were bringing up two cannon, which they trained on the Assassins fighting near Ezio. Soon afterward, as Ezio was cranking round and training the flamethrower on the nearest ships, he saw the puffs of smoke from the cannon mouths, then heard the crump of their detonations. The first cannonball fell into the water, short of where he was, but the second smashed into the jetty, making it lurch dangerously.