On the landing, the feeling of being watched built and built until I felt like screaming. It was so tangible, like there was someone standing right behind me, their eyes boring into the back of my head, or someone in the walls, or …

A hand fell on my shoulder. I jumped.

It was Kirsten. She gazed steadily into my eyes. “Hold it together,” she said, “Hold it together. I know what it feels like. But it can’t touch you. It can only affect your feelings. You can train yourself to ignore it.”

Details were blurring; I caught glimpses of dark corridors, broken windows; small steps up to a raised floor which led off to some other darkened niche. There was a heat in my stomach, rising. The staircase was plush red, steps descending (or were they ascending?) into shadow. The walls tilted dizzily around me, the floor lurching sickeningly. Was the whole thing alive? Had we entered the hot belly of a beast?

I’d never needed glasses. My sight had been perfect all of my life. But the walls were flickering, the floor, the ceiling. My damp clothes were hot, too damn hot. Vaguely I realised Kirsten was still holding my shoulder. My head was pounding. The world was about to flip …