Very slowly, Shadrach stalked like a predatory creature up the last of the stairs and past the door. He paused just before he reached it, and looked back and pointed at one of the monkey-constructs, then beside himself. He repeated the gesture. Isaac understood. He pulled himself close to the aural inputs of the construct and whispered instructions to it.

It scampered up the stairs with a quiet clatter that made Isaac wince, but the cactacae did not notice it. The construct squatted quietly down beside Shadrach, blocked from sight inside the room by his dark-drenched form. Isaac sent another construct to follow it, then signalled Shadrach to move.

At a slow, steady crawl, the big man crept in front of the doorway, shielding the constructs with his body. Their forms still caught the light, would glint as they passed the threshold. Shadrach moved without pause past the line of sight of the cactacae talking within, with the constructs creeping beside him hidden from the light, then on past the edge of the doorway into the darkness of the corridor beyond.

And then it was Isaac’s turn.

He indicated two more constructs hide behind his bulk, then began to crawl along the wooden floor. His belly hung down as he shuffled along with the constructs.

It was a frightening feeling, to move out from behind the wall and emerge in full view of the cactacae couple talking quietly as they stood ready to sleep. Isaac was huddled against the banisters on the hallway, as far from the door as he could go, but there were still several intolerable seconds when he crept through the dim cone of light towards the safety of the dark corridor beyond.

He had time to stare at the big cactus people standing in the hard dirt on the floor, whispering. Their eyes passed over him as he crept before their door, and he held his breath, but his thaumaturgic shadows augmented the darkness of the house, and he went unseen.

Then Yagharek, his scrawny form doing its best to hide the last of the constructs, crept past the light.

They regrouped before the next stairs.

“This section is easier,” whispered Shadrach. “There’s no one on the floor above, it’s just the ceiling of this one. And then above that…that’s where our slake-moths hide.”

Before they reached the fourth floor, Isaac tugged at Shadrach and pulled him to a stop. Watched by Shadrach and Yagharek, Isaac whispered again to one of the monkey-constructs. He held Shadrach still as the thing crept with mechanical stealth over the lip of the stairs, and disappeared into the dark room beyond.

Isaac held his breath. After a minute, the construct emerged and waved its arm jerkily, indicated them to come up.

They rose slowly into a long-deserted attic room. A window looked out onto the junction of the streets, a window without glass, whose dusty frame was scuffed with a variety of bizarre markings. It was through this little rectangle that light came in, a wan and changing exudation of the torches below.

Yagharek pointed at the window slowly.

“From there,” he said. “It came from there.”

The floor was littered with ancient rubbish, and thick in dust. The walls were scratched with unsettling random designs.

The room was traversed by a discomfiting river of air. It was a faint current, almost undetectable. In the motionless heat of the dome, it was unsettling and remarkable. Isaac looked around, trying to trace its source.

He saw it. Even sweating in the night-heat, he shivered slightly.

Directly opposite the window, the plaster of the wall lay in shredded layers across the floor. It had fallen from a hole, a hole that looked newly created, an irregular cavity in the bricks that raised to the height of Isaac’s thighs.

It was a glaring, looming wound in the wall. The breeze connected it and the window, as if some unthinkable creature breathed out in the bowels of the house.

“It’s in there,” said Shadrach. “That must be where they’re hiding. That must be the nest.”

Inside the hole was a complex and broken tunnel, carved into the substance of the house. Isaac and Shadrach squinted into its darkness.

“It doesn’t look wide enough for one of those bastards,” said Isaac. “I don’t think they work quite according to…uh…regular space.”

The tunnel was four feet or so wide, rough-hewn and deep. Its interior was quickly invisible. Isaac kneeled before it and sniffed deeply of the darkness. He looked up at Yagharek.

“You have to stay here,” he said. Before the garuda could protest, Isaac pointed to his head. “Me and Shad here, we’ve got the helmets that the Council gave us. And with this-” he patted his bag “-we might be able to get close to whatever, if anything, is in there.” He reached in and brought out a dynamo. It was the same engine the Council had used to amplify Isaac’s mindwaves, attracting his erstwhile pet. He also brought out a large tangle of metal-sheathed piping, coiled around his hand.

Shadrach kneeled next to him and lowered his head. Isaac slotted an end of piping into place on the helmet’s outlet, and twisted the bolts that held it.

“According to the Council, channellers use a setup like this for some technique called…displacement-ontolography,” mused Isaac. “Don’t ask me. Point is, these exhaust pipes will flush out our…uh…psychic effluvia…and discharge it out here.” He glanced up at Yagharek. “No mindprint. No taste, no trail.” He spun the last bolt firmly and rapped Shadrach’s helmet gently. He lowered his own head and Shadrach began to repeat the operation. “See, if there is a moth down there, Yag, and you go anywhere near it, it’ll taste you. But it shouldn’t taste us. That’s the theory.”

When Shadrach was done, Isaac stood and threw the ends of the piping to Yagharek.

“Each of those is about…twenty-five, thirty feet. Hang on to it till it’s taut, then let us go on with it trailing behind. All right?” Yagharek nodded. His stood stiff, angry at being left, but understanding without question that there was no choice.

Isaac took two coiling wires and attached them first to the motor he held, then slotted the other end of each into a valve on his and Shadrach’s helmets.

“There’s a little antacidic chymical battery in there,” he said, waving the engine. “It works in conjunction with a metaclockwork design pinched from the khepri. Are we ready?” Quickly, Shadrach checked his gun, touched each of his other weapons in turn, then nodded. Isaac felt for his flintlock and the unfamiliar knife at his belt. “All right then.”

He snapped the little lever on the dynamo. A little humming hiss emerged from the engine. Yagharek held the outlets dubiously, peered into them. He felt some vague sensation, some weird little wash, trembling through him from the rims of the pipes. A little tremble passed through him from the hands up, a tiny tremor of fear that was not his own.

Isaac pointed at three of the monkey-constructs.

“Go in,” he said. “Four feet ahead of us. Move slowly. Halt for danger. You-” he pointed at another “-go behind us. One stay with Yag.”

Slowly, one by one, the constructs trooped into the darkness.

Isaac briefly laid a hand on Yagharek’s shoulder.

“Back soon, old son,” he said quietly. “Watch out for us.”

He turned away and kneeled, preceded Shadrach into the shaft of shattered brick, crouching and working his way into the stygian hole.

The tunnel was part of a subversive topography.

It crept at bizarre angles between the walls of the terrace, tight and close, sending the sound of his breath and the clanking of the monkeys’ bouncing into Isaac’s ears. His hands and knees ached from the crushing pressure of the sharp stone-shards under him. Isaac estimated that they were moving back through the terraced houses. They were shuffling downwards, and Isaac remembered how the curve of the dome had decapitated the houses at a lower and lower point as they approached the glass. The closer the houses were to the edge of the dome, he realized, the lower they would be, the more filled with old wreckage.