The door was unlocked. Heather stepped into a small, filthy kitchen, thick with shadows. A square window let in enough moonlight for her to see a sink filled with dirty plates, an old wooden table riddled with burn marks and scratches, a packet of breakfast cereal open on the counter. There was an old-fashioned radio sitting on a cupboard shelf, and the wallpaper was peeling away in long, mouldy strips. The place was old and badly maintained, but also clearly still inhabited.

She moved out into the hallway beyond, which led at the far end to a staircase that turned back on itself. There was a door to either side – one, which was standing open, revealed a room used as both a living space and bedroom. She could see a vast lumpy sofa covered with sheets, a coffee table littered with cups, and as she moved into the room itself, piles of dirty clothes just thrown all over the floor. Her heart in her mouth, she checked in every corner, but the place was empty.

Perhaps he’s gone, she thought suddenly. Saw me coming and left. He could have left through the door, I couldn’t see when I was walking across the beach.

Or, suggested a darker part of her mind, perhaps this is a perfectly innocent house. Perhaps you have broken into the home of some poor, lonely soul, and you’re about to frighten the living shit out of them because you’ve lost touch with reality.

Heather backed out of the room and went to the closed door. Her hand on the doorknob, she paused as a painting on the wall next to it caught her eye. It was difficult to see in the gloom, but something about it made her fish out the phone from her pocket again, letting the screen light up the canvas briefly. It depicted a strange, red landscape, a flat and arid place with soft hills clouding the horizon. In the foreground, there was a single stunted tree, so twisted and black it almost looked like a crack in the arid ground, its sharp branches reaching like fingers. Heather swallowed and looked away. The painting frightened her.

As quietly as she could, she opened the door. Beyond it was a sheet of utter darkness, so she illuminated her phone again and cast the light ahead of her. There was a set of concrete steps leading down into a basement, and a strong smell of salt and bleach.

Heather made her way down the steps, tipping her makeshift torch into the room ahead. The floor was bare and stained, and a long sturdy table stood on one side, much newer and better cared for than the one in the kitchen. There was a large plastic storage box in one corner, filled with big industrial bottles of cleaning fluids and other things she didn’t recognize, and next to the table there was a metal trolley, littered with tools.