At the end of the street by the dome wall, under the stubby, boarded-up remnants of the house in which, Isaac realized, was the slake-moths’ nest, stood a gang of cactacae. Opposite them, where the road joined others and moved towards the temple at the dome’s centre, little groups of cactus warriors rushed by in either direction.

“Godspit, they must’ve heard all that ruckus,” hissed Isaac. “We have to damn well move, or we’re dead. One at a time.” He grabbed Yagharek and braced his arms behind the garuda’s back. “You first, Yag. You’re quicker and harder to see. Go. Go.” He pushed Yagharek out into the street.

Yagharek was not wrong-footed. He sprinted lightly, increasing speed. It was not panicked flight which might attract attention. He kept his pace just low enough that if one of the cactus people glimpsed motion, they might think it one of their own people. The shadows and stillness still varnished his fleeting figure.

It was forty feet to the darkness. Isaac held his breath, watching the muscles move beneath Yagharek’s scarred back.

The cactus people were jabbering in their harsh pidgin, arguing over who was to go in. Two swung huge hammers, taking turns to batter the bricked-up entrance to the last low house where, for all Isaac knew, the slake-moths and the Weaver still danced lethally together.

The darkness of the alley accepted Yagharek.

Isaac breathed deep, then stepped out into the alley himself.

He strode quickly away from the doorway, into the open street, willing his uncanny shade-covering to deepen. He began to jog towards the alleyway.

As he reached the midway point of the junction, there was a buffeting, a storm of wings. Isaac looked back and up at the window, on the vertex of the wedge of architecture.

Scrabbling at it with a repulsive desperation, the third slake-moth pushed its way through into the interior, returning home.

His breath caught, but the beast was ignoring him, its fervour reserved for its ruined spawn.

As Isaac turned his face again, he realized that the cactacae at the far end of the street had also heard the sound. From where they stood, they could not see the window, could not see the monstrous form infiltrating the house. But they could see Isaac running from them, fat and furtive.

“Oh shit!” breathed Isaac, and broke into a full, lumbering run. There was a confusion of yells. One voice rose above the shouting and snapped orders. Several cactus warriors broke away from the congregation by the door and ran straight for Isaac.

They were not fast, but neither was he. They carried their massive weapons expertly, unimpeded as they ran. Isaac sprinted as best he could.

“I’m on your damn side!” he shouted uselessly as he ran. His words were inaudible. Even if they had heard him, it was inconceivable that the cactus warriors, frightened and bewildered and pugnacious, would have paid any heed before killing him.

The cactacae were yelling, screaming for other patrols. There were answering shouts from neighbouring streets.

An arrow snapped from the alley before Isaac, whipping past him and thudding into some flesh behind. There was a gasp and a curse of pain from one of his pursuers. Isaac made out shapes in the darkness of the alley. Pengefinchess resolved from shadows, drawing back her bowstring once more. She bellowed at him to hurry. Behind her, Tansell stood with the blunderbuss drawn, aiming it uncertainly over her head. His eyes were scanning desperately behind Isaac. He shouted something.

Derkhan and Lemuel and Yagharek were crouched a little way behind, ready to run. Yagharek held his whip coiled and ready. Isaac raced into the darkness. “Where’s Shad?” screamed Tansell again. “Dead,” shouted Isaac. Instantly, Tansell screamed with horrible anguish. Pengefinchess did not look up, but her arm spasmed and she almost dropped her arrow. She paused and aimed again. Tansell shot wildly over her head. The blunderbuss boomed and he staggered with the recoil. A great cloud of buckshot sprayed harmlessly over the heads of the cactus people.

“No!” shouted Tansell. “Oh Jabber no!” He was staring at Isaac, begging to be told that it was not true.

“I’m sorry, mate, truly, but we have to fucking go,” said Isaac urgently.

“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. The vanguard of the group were startled by this strange, darkly shining figure with hands crooked like a vengeful skeleton, making the air crackle with charged thaumaturgons. Before they could react, Tansell let out a growl, and sizzling bolts of the black energy burst out of his body towards them.

They rolled like ball-lightning through the air and smacked into several cactacae. The hex strokes burst against their victims, dissipating across their skin in crackling veins. The cactus people flew yards backwards, slamming hard against the cobbles. One lay still. The others writhed, shouting in pain.

Tansell raised his arms higher, and a warrior stepped forward, his war-cleaver held way behind his shoulder. He swung it in an enormous, powerful arc.