“He’s right, Tan,” said Pengefinchess, her voice desperately steady. She fired another arrow, with the spring-loaded blade that sliced a great gouge of cactus flesh. She stood, notching a third missile. “Let’s go, Tan. Don’t think, just move.”

There was a high-pitched whirring, and a cactacae chakri slammed into the brick by Tansell’s head. It embedded itself deep, sending a painful explosion of mortar-shards around it.

The cactacae squadron were approaching fast. Their faces were visible, twisted in rage.

Pengefinchess began to back away, tugging at Tansell.

“Come on!” she shouted. Tansell moved with her, muttering and moaning. He had dropped the gun, was crooking his hands like claws.

Pengefinchess ran, dragging Tansell. The others followed her, turning into the intricate maze of backstreets through which they had arrived.

The air behind them hummed with projectiles. Chakris and thrown axe-knives whistled past them.

Pengefinchess ran and leapt at an amazing speed. She turned occasionally and fired behind her, hardly aiming, before resuming her run.

“Constructs?” she shouted at Isaac.

“Fucked,” he wheezed. “You know how to get back to the sewers?”

She nodded and turned a corner sharply. The others followed her. As Pengefinchess plunged into the decrepit alleyways near the canal where they had hidden, Tansell turned suddenly back. His face was deep red. As Isaac watched, some little vein burst in the corner of Tansell’s eye.

He wept blood. He did not blink. He did not wipe it away.

Pengefinchess turned from the end of the street and howled at him not to be stupid, but he ignored her. His hands and limbs were trembling violently. He raised his gnarled hands and Isaac saw that his veins were protruding hugely, like a map across his skin.

Tansell began to pace back along the street, towards the turnoff where the cactacae would emerge.

Pengefinchess screamed for him one last time, then leapt mightily over a crumbling wall. She shouted for the others to follow her.

Isaac backed quickly towards the shattered brick, his eyes fixed on Tansell’s retreating figure.

Derkhan was scrambling up a little stairway of broken brick, hesitating and leaping down into the hidden yard where the vodyanoi wrestled with the manhole cover. It took Yagharek less than two seconds to scale the wall and drop to the other side. Isaac reached up and looked behind him again. Lemuel was running quickly down the alley, ignoring the desperate figure of Tansell behind him.

Tansell stood at the entrance to the alleyway. He shook with effort, his body coursing with thaumaturgic flow. His hair stood on end. Isaac saw little ebony sparks burst outwards from his body, snapping arcs of energy. The puissant charge that snapped and burst out from under his skin was absolutely dark. It glowed negatively, with unlight.

The cactacae turned the corner and were upon him.