On the way up the stairs, the heat was rising. I heard Kirsten breathe in sharply as she noticed it. Like a jet of air from a carelessly opened oven, it pressed onto our faces, embraced us with an intimacy beyond that which flesh could offer. It was inside us, our stomachs filling with a wave of intensity, a roasting pain.

I knew we were only a few steps up, but we seemed to have risen so high, the walls twisting and shifting on either side. I was conscious of intricate detail as we passed, but to look sideways was impossibly unsteady. I tried to crouch low, to touch the stairs, but it was like the air had become one-way, only letting us move upwards to ever greater, ever more dangerous heights. For an instant I saw flames licking up the walls, then they were clear and the landing was a faint shape ahead.

On the second-last step, my balance went and the landing seemed to turn dementedly.