Then Isaac blinked and stared down at Lin, who slumped in his embrace.

He hissed at her, shook her.

“Lin,” he whispered. “Lin…We’re leaving.”

Yagharek strode quickly over to the window and peered out over the street five floors below. Next to the window, a little jutting column of brick extended out from the wall, becoming a chimney. A drainpipe snaked up beside it. He stood quickly on the window-sill and reached up for the guttering, tugged it quickly. It was solid.

“Isaac, bring her here,” said Derkhan urgently. Isaac lifted Lin up, biting his lip at how light she was. He walked quickly with her to the window. As he watched her, his face suddenly broke into an incredulous, an ecstatic smile. He began to weep.

From the passage outside, the slake-moth keened weakly.

“Dee, look!” he hissed. Lin’s hands were fluttering erratically in front of her as he cradled her. “She’s signing. She’s going to be all right!”

Derkhan peered over, reading her words. Isaac watched, shook his head.

“She’s not conscious, it’s just random words, but, Dee, it’s words…We were in time…”

Derkhan smiled in delight. She kissed Isaac hard on the cheek, stroked Lin’s broken headscarab gently.

“Get her out of here,” she said quietly. Isaac peered out of the window, where Yagharek had wedged himself into a corner of architecture, on a little extrusion of brick a few feet away.

“Give her to me, and follow,” said Yagharek, jerking his head up above him. At the eastern end the long sloped roof of Motley’s terrace joined with the next street, which jutted perpendicularly south in a descending row of houses. The roofscape of Bonetown stretched out above and all around them; a raised landscape; linked islands of slate over the dangerous streets, extending for miles in the darkness, sweeping away from the Ribs to Mog Hill and beyond.

Even then, devoured alive by tides of fire and acid, stunned with bolts of obscure energy, the last slake-moth might have survived.

It was a creature of astonishing endurance. It could heal itself at frightening speeds.

If it had been in the open air, it could have leapt up and spread those terribly wounded wings and disappeared from the earth. It might have forced itself up, ignoring the pain, ignoring the scorched flakes of skin and chitin that would flutter around it filthily. It could have rolled into the wet clouds to douse the flames, wash itself free of acid.

If its family had survived, if it had been confident that it could return to its siblings, that they would hunt together again, it might not have panicked. If it had not witnessed a carnage of its kind, an impossible blast of poisonous vapour that enticed its brothersisters in and burst them, the moth would not have been insane with fear and anger, and it might not have become frenzied and lashed out, trapping itself further.

But it was alone. Trapped under brick, in a claustrophobic warren that constricted it, flattened its wings, left it nowhere to go. Assailed on all sides by murderous, endless pain. The fire came and came again too fast for it to heal.

It staggered the length of the corridor in Motley’s headquarters, a white-hot ball, reaching out to the last with ragged claws and spines, trying to hunt. It fell just before the top of the stairs.

Motley and the Remade looked on in awe from halfway down, praying that it lay still, that it did not crawl over the lip of the stairway and tumble flaming onto them.

It did not. It was still while it died.

When they were sure the slake-moth was dead, Motley sent men and women up and down the stairs in quick columns, carrying sodden towels and blankets to control the blaze it had left in its wake.

It took twenty minutes before the fire was subdued. The beams and boards of the attic were split and smoke-fouled. Massive footprints of charred wood and blistered paint stretched the length of the passage. The smouldering body of the moth rested on the top of the stairs, an unrecognizable pile of flesh and tissue, twisted by heat into an even more exotic shape than it had had in life.

“Grimnebulin and his bastard friends’ll be gone,” said Motley. “Find them. Find where they went. Track them down. Trace them. Tonight. Now.”

It was easy to see how they had escaped, out of the window and onto the roof. From there, though, they could have gone in almost any direction. Motley’s men shifted, looking uneasily at each other.

“Move, you Remade scum,” raged Motley. “Find them now, track them down and bring them to me.”

Terrified gangs of Remade, of humans, of cactacae and vodyanoi set out from Motley’s terrace-den, off into the city. They made pointless plans, compared notes, frantically raced down to Sunter, to Echomire and Ludmead, to Kelltree and Mog Hill, all the way to Badside, over the river to Brock Marsh, to West Gidd and Griss Fell and Murkside and Saltpetre.

They might have walked past Isaac and his companions a thousand times.

There was an infinity of holes in New Crobuzon. There were far more hiding places than there were people to hide. Motley’s troops never had a chance.

On nights like that one, when rain and streetlamp light made all the lines and edges of the city complex-a palimpsest of gusting trees and architecture and sound, ancient ruins, darkness, catacombs, building sites, guesthouses, barren land, lights and pubs and sewers-it was an endless, recursive, secretive place.

Motley’s men made their way home empty-handed and afraid.

Motley raged and raged at the unfinished statue that taunted him, perfect and incomplete. His men searched the building, in case some clue had been missed.

In the last room on the attic corridor, they found a militiaman sitting with his back to the wall, comatose and alone. A bizarre, beautiful glass flintlock lay across his lap. A game of tic-tac-toe was scratched into the wood by his feet.

Crosses had won, in three moves.

We run and hide like hunted vermin, but it is with relief and joy.

We know that we have won.

Isaac carries Lin in his arms, sometimes hauling her over his shoulder apologetically when the way is tough. We race away. We run as if we are spirits. Weary and exhilarated. The shabby geography in the east of the city cannot restrain us. We clamber over low fences and into narrow swathes of backyards, rude gardens of mutant apple trees and wretched brambles, dubious compost, mud and broken toys.

Sometimes a shade will pass across Derkhan’s face and she will murmur something. She thinks of Andrej; but it is hard that night to retain guilt, even when it is deserved. There is a sombre moment, but under that spew of warm rain, above the city lights that bloom promiscuous as weeds, it is hard not to catch each other’s eyes and smile or caw softly in astonishment.

The moths are gone.

There have been terrible, terrible costs. There has been Hell to pay. But tonight as we settle in a rooftop shack in Pincod, beyond the reach of the skyrails, a little way north of the railway and the squalor of Dark Water Station, we are triumphant.

In the morning, the newspapers are full of dire warnings. The Quarrell and The Messenger both hint that severe measures are to come.