Petrovitch put his finger to his lips and pointed upward.

She followed his direction, and stared for a few moments. Then she looked down at him and hissed, “We’ll bring you back up.”

He shook his head, and she looked up again, just to check she’d seen what she thought she’d seen.

“Really, we’re bringing you back up.”

He shook his head harder and pointed down. They looked at each other for a while, and he could hear Madeleine’s voice rise in pitch as she asked repeatedly what was going on.

Then he started to slide down the face of the wall. Eventually, his questing feet found the floor, and the rope slackened. Tabletop used that slack to go hand-over-hand, her legs wrapping around the nylon to control her descent. It took seconds, and then she was untying him.

“We have to be insane to even attempt this,” she said.

“I never said it was going to be easy.”

“I’m pretty sure you did.” The rope slipped off his exoskeleton and slithered away.

“If Tina’s blasting hasn’t brought it down, there’s no reason to believe anything we do will.”

“Then why,” said Tabletop, “are we whispering?”

“Because it looks yebani scary, that’s why. If we’re very, very quiet, it might not notice us. Primal memories from the dawn of time: we’re nothing but cavemen, really.”

“Then let’s drag our knuckles over to the door and get through it.”

It was a few short steps to the alcove. Inset were blank steel doors, tall and wide enough when both open to wheel the quantum computer out and into the shaft. Petrovitch tried an experimental tug on one of the handles.

“Yeah, that’s locked.”

He looked at the walls on either side of the doors, then at the face of the doors themselves.

“This isn’t looking good,” murmured Tabletop.

“Found it.” He crouched down and gently blew the dust away from the mechanism. A tiny red light showed through the grime, halfway up the right-hand door. “Oh, you have got to be joking.”

“It’s a…”

He scrubbed at it with his sleeve. “… fingerprint scanner. That’s it. That’s the only way in.”

“Shall I go and get Valentina?”

Petrovitch glanced at the great bolus of debris hanging over them. His face twitched. “I’m going to try something first.”

He licked his right index finger to clean it, then dried it carefully on his collar. He puffed again at the tiny glass window on the lock, and grimaced as he pressed his finger to it.

The red light winked off, and a green one glimmered on. Locks and bolts unwound and slid aside, winding back with oiled understatement.

Petrovitch tried the handle again. The door swung open a little way, then grounded itself on some debris underfoot. He kicked it out of the way and scraped his boot along the arc the door had to describe.

“I take it that wasn’t luck,” said Tabletop.

“No. No it wasn’t.” He held the door aside and Tabletop slipped through. He raised his hand to the faces at the tunnel, and followed. He wedged a piece of fallen concrete in the gap to stop the door clicking shut again.

Just in case.

They were in a short corridor, with another set of double doors at the end. The recessed lights stayed dark, and everything was silent and still.

“Okay?” Petrovitch’s clothes rustled as he moved.

“Nervous.”

“Yeah. I know how that goes.” His boots squeaked on the rubber floor as he walked.

The other doors were merely closed, on the premise that if someone had got this far, they were clearly authorized to be there. But there was a resistance to them opening: a positive pressure from inside, forming a seal. He shoved hard, and there was an audible pop of air.

He held the door ajar, took a deep breath and opened it further. The room beyond was utterly black, cold, sterile.

“Touch nothing,” he said. “Stick to the walls, if we can find out where the huy the walls are.”

He edged in, feeling his way. Tabletop slipped in after him, and the door whuffed shut. There was something in here that still worked, then, producing that current of air.

He heard the sound of Velcro unfastening, then the tiny screen on Tabletop’s forearm bloomed into life. It produced a tiny amount of light, no more than a candle’s worth, but in the absence of anything else, its effect was dramatic.

The room was as tall as it was wide: a perfect white cube, at the center of which was another, smaller, perfectly black cube on a raised platform.

“My God, it’s full of stars.”

“Sorry?”

“Don’t worry. Even if you’d seen the film or read the book, they’ve probably erased your memory of it. Old Man Oshicora had a sense of humor, as well as being a cold-hearted murderer. I suppose the two aren’t mutually exclusive.” Petrovitch stepped slowly over to the cube, aware of all the dirt he was trailing behind him. He laid his hand on the smooth surface of the quantum computer. “Dobre den, tovarisch.”

“You think he’s in there?”

“Who do you think reprogrammed the door lock? He survived the collapse of the tower. His life support was still functioning. If I’d been him, I would have cut my power consumption to a minimum, and then just…”

“Just what?”

“I don’t know. Go to sleep, maybe. Dream. When Oshicora dreamed, he created the New Machine Jihad. But Michael’s not like that. I think his dreams will be something altogether more grand.”

“For a whole year?”

“Chyort. Even I feel like I could sleep for a year.” He bowed his head and let it hang. “I am so very tired. Tired of planning and plotting and worrying and trying to keep it all together for so very long.” He patted the computer. “We’re almost there. One last push. Come on, let’s see if we can’t wake Sleeping Beauty.”

There were no obvious consoles or interfaces. Everything was neat, clean, almost zen in its simplicity. Oshicora again.

They worked as a pair, Petrovitch feeling his way around the base of the cube, Tabletop behind him, providing illumination. “Where’ve you hidden it?” They’d gone around all four sides, and were stumped.

“Do you think he made it deliberately difficult?”

“No, which is why I think I’m missing something completely obvious.” His fingertips drifted off the horizontal surface and onto the vertical face of the step. There was a lip, very slight, but enough for him to catch his nails against.

He shook his head and lifted the whole step up to reveal a row of controls and displays. Tabletop rolled her eyes and hunkered down next to Petrovitch to inspect what they’d found.

The screens were all blank. No lights were showing.

“We might be too late,” she said.

“No. All this is off because Michael had settled in for the long wait. One little LED might make the difference between having enough watts to keep cool and eventual heat death.”

They lifted the other steps, and on the last one, they found a network port. Petrovitch pursed his lips, then reached under his T-shirt for the palmtop taped to his side.

“In the absence of any big button saying ‘on,’ I’m going to have to go in.” He looked up at Tabletop’s shadowed face. “I’m going to need your help.”

“Unplugging yourself: what’s that going to do to you?”

He sat back on his heels. “The last time it rendered me insensible. The time before that, too. I’ve been dragging this arm around behind me for a day, banging it about and generally mistreating myself, so I kind of figure that it’s going to be even worse than that.”

“And when you plug into Michael? What if you can’t cope without your programs and protocols?” She held her hand out and Petrovitch placed the palmtop into it.

“You’re going to have to use your judgment. If it looks like I’m dying, don’t disconnect me.” The corner of his mouth twitched. “Only do that if I’m actually dead.”

“Seriously?”

“Yeah. It seems we have a short period of grace before our brains go hypoxic.”