“Now, for many reasons that we have discussed, not least our somewhat different working methods, we don’t believe it would be particularly fruitful to combine our patrols. However, it most certainly does make sense to co-ordinate our efforts. That is why we have extended a legal amnesty for your organization during this collaborative mission. In similar vein, we are prepared to offer a temporary waver of the strict rule against non-governmental aerostats.”

She cleared her throat. We’re getting desperate, she thought. But then, so, I wager, are you.

“We are prepared to loan two airships, to be used after discussion with us on suitable routes and times. This is in an effort to divide up our efforts to hunt, as it were, in the skies. Our conditions remain as previously stated: all plans to be discussed and agreed in advance. In addition, all research into hunting methodology to be pooled.

“So . . .” she sat back and dropped a contract across the desk. “Do you have authority with Motley to take this kind of decision? And if so . . . what do you say?”

When Isaac, Derkhan and Yagharek pushed open the door of the little shack by the railway and fell into its warm shadows, exhausted, they were only a little surprised to see Lemuel Pigeon waiting for them.

Isaac was surly and foul. Pigeon was unapologetic.

“I told you, Isaac,” he said. “Don’t get confused. Going gets hot, I’m gone. But here you are and I’m glad to see it, and our deal still stands. Assuming you still insist on hunting those fuckers, I’m going to own you, and until then you get my help.”

Derkhan glowered, but she did not indulge anger. She was tense with excitement. She glanced at Isaac quickly and frowned.

“Can you get us into the Glasshouse?” she said.

She told him, briefly, about the immunity of the Construct Council from slake-moth attack. He listened in fascination as she described how the Council had swivelled the crane behind the moth’s back, released it and pinioned the thing mercilessly under tons of rubbish. She told him how the Construct Council was sure the moths were in Riverskin, hiding in the Glasshouse.

Derkhan told him the tentative plans.

“Today we have to find some way to make the helmets,” she said. “Then tomorrow . . . we go in.”

Pigeon’s eyes narrowed. He began to scribble designs in the dust.

“This is the Glasshouse,” he said. “There are five basic routes in. One involves bribery, and two almost certainly involve killing. Killing cactacae’s never a good idea, and bribery’s risky. They talk and talk about how they’re independent, but the Glasshouse survives on Rudgutter’s sufferance.” Isaac nodded and glanced at Yagharek. “That means there’s loads of informers. Secrecy’s safer.” Derkhan and Isaac leaned over him, watched his hieroglyphs take shape. “So let’s concentrate on the other two, see how they pan out.”