"When we met on the Terpsichoria, I was in something of a state, I remember. I told you I had to return to New Crobuzon immediately. You reminded me of that yourself, recently. And I told you that I’d been lying. But I wasn’t. What I said on Terpsichoria was true: I have to return. Dammit, you probably realized all this."

Bellis said nothing.

"I didn’t know how to… I didn’t know if I could trust you, if you’d care," he continued. "I’m sorry I wasn’t honest with you, but I didn’t know how far I could go. But dammit, Bellis, I trust you now. And I need your help.

"It’s true, what I told you, that sometimes the grindylow turn against some poor sod for no reason anyone can figure. That people disappear at their whim. The grindylows’ whim, the deeplings." But it’s not true, what I said then, about that happening to me. I know exactly why the grindylow wanted to kill me.

"If they chose, the grindylow could swim upriver to the top of the Bezheks, where all the rivers join together, and they could cross into the Canker. Be swept downriver on the other side of the mountains, all the way to New Crobuzon.

"Others could cross into the ocean through the tunnels, come at the city by sea. They’re euryhalinic, the grindylow, happy in freshwater or brine. They could make their way to Iron Bay. To the Gross Tar, and New Crobuzon. All it would take for the grindylow to get to the city is determination. And I know they have that."

Bellis had never seen Silas so tense.

"When I was there, there were rumors. Some big plan was in the offing. One of my clients, a magus, a kind of thug-priest, its name came up again and again. I started to keep my eyes and ears open. That’s why they want to kill me. I found something out.

"The grindylow don’t do secrecy; they don’t do policing as we do. There was evidence in front of me for weeks, but it took me a long time to recognize it. Mosaics, blueprints, librettos, and such-like. Took me a long time to understand."

"Tell me what you found," said Bellis.

"Plans," he said. "Plans for an invasion."

"It would be like nothing you can imagine," he said. "Gods know our history’s littered with betrayal and fucking blood, but… ‘Stail, Bellis… You’ve never seen The Gengris." There was a desperation in his voice that Bellis had never heard before. "You’ve never seen the limb-farms. The workshops, the fucking bile workshops. You’ve never heard the music.

"If the grindylow take New Crobuzon, they wouldn’t enslave us, or kill us, or even eat us all. They wouldn’t do anything so… comprehensible."

"But why?" said Bellis, finally. "What do they want? Do you think they can do it?"