In the very last tank, Sebastian Drood came forward to stare mockingly at us as we stopped before the air lock. As the most dangerous, he had a cell all to himself. He looked normal enough now, though there was something wrong with his face, as though he’d forgotten how to look human. Or perhaps he just didn’t feel the need to bother any more. He nodded politely to me, and smiled at Molly.

“Dear Molly,” he said. “How does it feel, to be one of us?”

“I’ll never be one of you,” she said steadily. “Whatever it takes.”

“Ah,” he said, shrugging easily. “You say that now . . . but we all start out feeling that way. We don’t turn ourselves in, like we know we should, because we’re different. We’re strong, we can beat this. We’ll never give in; no, not us. But after a time . . . you won’t want to fight it. In fact, you’ll embrace it. Because being human is such a small thing to leave behind.” He turned abruptly to look at me. “You haven’t told anybody about her, have you, Eddie? I counted on that. And by the time you realise how hopeless it is, it’ll be too late. Is that why you’re here, Eddie? To kill me before I can tell anyone what I did to dear Molly? Am I to be destroyed while trying to escape?”

“Say what you like,” I said. “No one will believe you. A drone would say anything, tell any lie, to try and undermine the family.”

“Then why are you here?” said Sebastian. “Hoping for a cure, perhaps? Don’t waste your time and mine. There isn’t one. Once someone is one of us, they’re one of us forever.”

“You could do yourself some good,” I said. “Win yourself some better treatment by agreeing to answer a few questions.”

“And don’t waste any time on lies,” said Molly. “I’d know.”

“Yes,” said Sebastian. “You would. Very well, ask your questions.”

“Who was the original traitor?” I said. “Who worked to persuade the family to bring the Loathly Ones back, in 1941?”

“Haven’t a clue,” Sebastian said cheerfully, leaning on the steelglass with his arms folded. “And in case you were thinking of threatening me with truth spells or cattle prods or whatever we use for interrogation these days, yes, I know we’re a hive mind, but we’re kept strictly compartmentalised. Each drone only knows what it needs to know, when it needs to know it. Basic security. I might have known who the traitor was once, but I am currently cut off from that area of knowledge. Or indeed any area that might help you. Same with all the drones here.”

“There are ways of digging out the truth,” I said. “Old ways. Of course, they can be very destructive, to the body and the mind . . .”