Page 217 of The Sleepwalker

Once everyone is in position, Thor and his partner walk down the paved path to the front door with their guns lowered.

The house is dark.

The storm tugs at the trees and bushes, and one of the men has to duck as a red plastic sledge blows over the fence.

Thor glances down at his watch and gives the order. His men break three windows and toss tear gas canisters inside.

They force the door at the rear of the property while Thor does the same at the front.

Nolan heads in first, with his rifle raised.

Thor follows him in, and their tactical lights sweep through the thick tear gas, over the walls and the coats hanging on hooks, flashing in a mirror.

On Saturday, his wife Kristina left the house wearing nothing but a pink camisole. He realised she must have taken too much of her medication when he spotted her through the kitchen window, feet bright red from the cold, plasters on both knees and dark pubic hair bared for all to see. She got into the car and reversed straight into the hedge, where she got stuck.

By the time he got to her, she had thrown up all over herself, and the white froth from the partially broken-down pills was clinging to the corners of her mouth.

He got her back into the house, and she started rambling incoherently about an old man who suffocated himself with a dildo. Repeating that there is a crackling grey force beneath all staircases, trying to make weak people stop breathing.

Once the ambulance had taken her away, Thor slumped down on the unmade bed and cried in a way he hadn’t since he was a boy.

Nolan clears the toilet to the left.

Thor steps over a pair of black rubber boots on the brown-tiled floor and makes his way through to the kitchen, quickly swinging around to one side as Nolan moves past him and checks the other.

The knives gleam in the light from their rifles.

Thor finds himself staring at the reflection of the kitchenin the dark window: Nolan turning without a sound and being swallowed up by the black doorway.

A small blob of gun grease glistens on the barrel of his rifle.

Thor licks his lips, turns around and thinks about the fact that Kristina’s frightened ideas often revolve around the underside of staircases.

She has told him about the two young boys who were found suffocated when she was a girl. They were sitting opposite each other beneath a staircase at the end of a bridge, their mouths and throats packed with clay.

He hears the heavy footsteps of the rest of his team, and he follows Nolan into a smoky living room, secures the right-hand side and sees tactical beams sweeping past the stairs to the floor above.

The shadows from the spindles spread like fingers on the wall, and shards of glass from one of the broken windows glitter on the blue carpet.

For a few seconds, in the smoke drifting through the house and the shafts of lights cutting through the darkness, Thor feels as though he has slipped into some kind of alternate reality.

Everything becomes hollow and echoing.

The wooden floor beneath the rug creaks as he moves forward.

On a shelf, gaudy souvenirs cast sloping shadows against the wall.

The door of a sideboard slowly swings open.

Thor tries to swallow his anxiety as he makes his way over to the stairs.

He hears a metallic thud underfoot, as though he has just stepped on a metal hatch or the floor of a construction lift.

Nolan shouts something from behind his mask.

In the corner beneath the stairs, the smoke is twisting like a tornado, a rotating column. Thor swallows, and his mindhas just drifted back to Kristina’s words about the suffocating forcefield when Nolan runs past him and up the stairs.

As though in a trance, Thor lumbers after him, staring down at the smoke between the steps, the way it is writhing in the corner. He pauses and pokes himself in the mouth, but is dragged back to reality when he hears Nolan fire his Heckler & Koch on the first floor.