Derkhan bellowed with triumph, her cry becoming words. “Die, you swine!” she screamed. She ducked back out of sight as a rapid battery of shots smacked into the brick and stone above and below her.

Isaac dropped onto all fours beside her, staring at her. It was impossible to say, in the rain, but he thought she was sobbing angrily. She rolled back from the edge of the roof and began to reload her pistols. She caught Isaac’s eye.

“Do something!” she screamed at him.

Yagharek was standing, hanging back from the edge, grabbing glimpses every few seconds, waiting until the men were in reach of his whip. Isaac rolled forward, peered over the rim of the little platform. The men were drawing nearer, moving more carefully now, hiding at each level, staying out of sight, but still moving terribly fast.

Isaac aimed and fired. His bullet burst dramatically against slate, showering the lead militiaman with particles.

“Godsdamnit!” he hissed and ducked back to refill his gun.

A cold certainty of defeat was settling within him. There were too many men, coming too quickly. As soon as the militia reached the top, Isaac would have no defence. If the Weaver came to their aid they would lose their bait, and the slake-moths would escape. They might take one, two or three of the officers with them, but they could not escape.

Andrej was jerking up and down, arcing his back and straining against his bonds. The nerves between Isaac’s eyes were singing as the blast of energy continued to scald the æther. The airships were pulling near. Isaac screwed up his face, looked back over the edge of the plateau. On the broken plain of the roof below, drunkards and vagrants were rousing themselves and scurrying away like terrified animals.

Yagharek screeched like a crow and pointed with his knife.

Behind the militia, on the flattened roofscape they had left behind, a cloaked figure slipped out of some shadow, appearing like an eidolon, manifesting as if from nothing.

There was a flurry of bottle-green from its coiling cloak.

Something spat intense fire and noise from the figure’s outstretched hand, three, four, five times. Halfway up the slope, Isaac saw a militiaman bow away from the roof, collapsing in an ugly organic cascade down the length of the clay. As he fell, two more of the men staggered and collapsed. One was dead, blood pooling below his sprawled body and diluting in the rain. The other slid a little way and emitted a horrendous shriek from behind his mask, clutching at his bleeding ribs.

Isaac gazed in shock.

“Who the fuck is that?” he shouted. “What the fuck is going on?” Below him, their shadowed benefactor had ducked into a puddle of darkness. He seemed to be fumbling with his gun.

Below them, the militia had frozen. Orders were shouted in impenetrable shorthand. It was clear that they were confused and afraid.