Lemuel was confident. He swung his primed and loaded pistol easily as he climbed and ran, keeping them covered. Yagharek had adapted to his body without the weight of wings. His hollow bones and tight muscles moved efficiently. He swung lithely over the architectural landscape, leaping obstacles in the slate. Derkhan was dogged. She would not let herself fail to keep up.

Isaac was the only one whose suffering showed. He wheezed and coughed and retched. He hauled his excess flesh along the thieves’ trails, breaking slates with his heavy slapping footfall, cradling his belly miserably. He swore constantly, every time he exhaled.

They cut a trail deeper into the night, as if it were a forest. With every step, the air grew heavier. A sense of wrongness, of fraught unease, as if long nails scraped the surface of the moon, raising the hackles of the soul. From all around them came the cries of miserable, disturbed sleep.

They stopped in Flyside, a few streets from the militia tower, and took water from a pump to wash and drink. Then south through the morass of alleys between Shadrach Street and Selchit Pass, bearing down on Aspic Hole.

And there in that near-deserted and unearthly place, Isaac had bade his companions wait. Between sobs of desperate breath, he begged them to wait, to give him half an hour with her.

“You’ve got to give me a little while to explain to her what’s going on . . .” he pleaded.

They acquiesced, and hunkered down in the darkness at the base of the building.

“Half an hour, ’Zaac,” said Lemuel clearly. “Then we’re coming up. Understand?”

And so Isaac had begun slowly to climb the stairs.

The tower was cool and quite silent. On the seventh floor, Isaac heard sound for the first time. It was the sleepy murmur and unceasing flutter of jackdaws. Up again, through the breezes that passed through the ruined and unsafe eighth floor, and on to the building’s crest.

He stood before Lin’s familiar door. She may not be there, he reasoned. She’s probably still with that guy, her patron, doing her work. In which case I’ll just have to . . . leave a message for her.

He knocked at the door, which fell open. His breath stalled in his throat. He rushed into the room.

The air stank of putrefying blood. Isaac scanned the little attic space. He caught sight of what awaited him.