Benjamin’s face was a snarl. Charles was guarded, worried. It was he who said, “Jindal, get Burnofsky up here.”

Keats had reached the optic nerve. He sank a probe. “I can see,” he said in a dreamy, disconnected, emotionless voice. “Caligula is looking right at it. At the bomb. There’s a timer.”

“How much time left?” Jindal asked.

Benjamin raged at him. “Follow my brother’s orders, now!”

“I have a weak picture,” Keats said, speaking to Plath. “I’ll try for a better one.”

Jindal rapped orders to his people, then, undeterred—Accustomed to abuse, Keats thought—he said, “Our people will be through the door into the sublevel in a few minutes.”

“How are they getting through?” Plath asked.

“They’re cutting through the steel with a blowtorch and once they’re in—”

“A blowtorch? Cutting into a room full of gas?” Wilkes cried. “Isn’t that, uh, stupid?”

“She’s right,” Charles said.

“No,” Plath said sharply. “No. Maybe better to blow it up now rather than wait. Less gas now. More later.”

“System,” Charles said. “Exterior, sublevel doors.”

As one they all turned to look at the monitor. Four frames. Three showed nothing but doors. The last showed two men wearing welding helmets. The bright light of the torch caused lens flares that obscured the progress of the work.

“Seven minutes, eighteen seconds,” Keats said. “I can see it now. I can see it clearly. Seven minutes and …” And it all came back to him. The calm of battle had run its course once his biot had reached its goal. Now Keats couldn’t go on. He had run out of indifference to his own fate.

Part of him didn’t want to tell Sadie. What would be gained? But he had to speak. He had to say good-bye.

“Sadie,” he said.

She must have registered the sadness and gentleness in his voice. She turned to him. “Yes?”

“Sadie,” he said again. “I’ve thought about it a lot. I’ve seen Alex. I know what it means. Death or madness, I … I guess I believe in another life, maybe. After this one. So …”

She stared, uncomprehending. Then a sharp intake of breath. Her eyes widened. “Oh, God.”

“What?” Wilkes demanded.

“I’m getting my other biot as far from your aneurysm as possible,” he said. “But you’ll need to kill me. You can’t have it in your head with a madman running it.”

“Noah,” Sadie said. Sadie, and not Plath. Sadie. “Noah … We have to …”

He took her hand in his. “We always knew it could happen.”

“Order the men down there to cut straight through, forget cutting a hole, tell them just to cut all the way through in a single spot,” Benjamin told Jindal.

“Better to burn than to blow up,” Benjamin said. “And thus, it ends.”

“You can’t … Noah …”

“When Caligula burns, so will my biot, Sadie. You know what follows. It’s okay.”

“Noah …” She was in his arms, and tears were running down her face.

“Yes, of course, pity for the pretty boy, eh?” Benjamin said savagely. “Pity for poor, poor Noah. None for our people on our beautiful ship. And none for hideous freaks.”

Burnofsky watched the counter on his computer monitor. The number of self-replicating nanobots had just crossed thirty-two million. The next doubling would take it to sixty-four million, then one hundred and twenty-eight. Pretty soon megabots would give way to gigabots and hence to terabots.

He laughed at that, slurred, “I made a funny,” took a drink, sucked on his cigarette, and touched the butt of the pistol that was stuck into his belt.

He’d been feeding the nanobots everything he could find: stale doughnuts, candy bars from the machine down the hall, half a salami he’d found in the staff fridge. He hadn’t slept in … how many hours? How many days? It was all kind of fuzzy.

He had the remote control in his hand. Press the button and the force field would drop. His nanobots would eat their way out into the world and from there they would never stop. They would eat their way through the building, its furnishings, and anyone dull enough to wait around.

But before they finished the Tulip they’d be carried on breezes or simply fall from chewed-through walls down onto the streets. Nearby buildings would be infested and begin the same accelerated decline and rot. The pace would accelerate as the nanobots doubled and doubled.

What would the reaction be? What would the government do? Nothing short of a nuclear weapon would stop the spread, and they would wait far too long for that. Nanobots would find their way onto ferries, cars, ships, and planes.

For the first few days the damage would be most visible at the epicenter. But then, here and there and all around the world they would appear and double and double and double.

People would flee to the woods and deserts. And they would survive for a while—maybe weeks, maybe months. In places the nanobots would consume all there was to consume and cease doubling. But by that time they would have eaten every living thing and much of the nonliving things as well.

He asked himself, where would be safe? Or at least, where would be safest? The coldest places, he supposed. Nanobots tended to be immobilized when things got cold enough, down to minus twenty-three Celsius or minus ten Fahrenheit. But even in the coldest lands a warm day would set them off again.