“I’ll try with, then try without. And I’m going to use some real data, whether you like it or not.”

“Experimentalists. Have I told you how much I hate them?”

“Only about a thousand times.” Petrovitch shrugged. “Science: it works.”

Pif drank her coffee, and summoned enough strength to pick up her rucksack. “Are you sure about this?”

“Go,” he said. “See you in the morning. You can go through my shabby math while I cringe pathetically in a corner, then I can watch you reimagine the whole universe.”

She slung the rucksack over her shoulder. “If you put it like that, I don’t see how I can argue.”

“I might even get some of my own work done. You never know.”

“Boys and their toys,” she said, edging toward the door. “Sam, are you…?”

“Go away. There won’t be any sleep for a week if you crack this.”

She bowed her head, her beaded hair falling forward like a curtain. “Sam?”

“What?”

“I’m glad I’m sharing a room with you. You get me.”

“You mean you’re as dysfunctional as I am, just in different ways? Yeah, that’s about right. Now, in the name of whatever god you believe in, go.”

She nodded. She was halfway out into the corridor when she stopped. “What?” she said with typical directness.

“Police,” said a familiar voice.

“Chyort voz’mi!” He launched himself into his chair and folded his arms.

Pif put her head back around the door. “Sam? There’s a policeman here.”

“I know. Send him in, then go home. I’ll be fine.” He pushed his glasses up his face. “He’s not staying for longer than he absolutely needs to. Which is about a minute, if he’s lucky.”

Chain wandered in, blinking. “Petrovitch.”

“Detective Inspector Chain. Found my rat yet?”

“Ongoing inquiries,” he said. He glanced down at Pif’s desk and reached out to pick up one of her equations.

Petrovitch leaped up and slapped his hand down on top of the paper. “Touch nothing. Really.”

Chain held his hands up. “It didn’t look like it was going to break, but if you insist.” He looked around. “I was expecting big machines that sparked and hummed.”

“We keep those in the basement next to the reanimated bodies. What do you want?”

“Oh, I don’t know. How about five hundred thousand euros?”

“Back of the queue, Inspector. I have to be dead before you collect.”

“You think you’re smart?”

“I think I now stand a better chance of staying alive than I would relying on you. And thanks ever so much for sending Sorenson around. Not only did it get us both picked up by Marchenkho, I then had to get farmboy back to Oshicora before he realized his pet coder had gone awol.”