Loo placed her hands on the window ledge again and leant as far forward as she dared. As she watched everyone, it seemed to her that she could feel something underneath the paint, inside the wood, a sort of humming, and the more she concentrated on that, the clearer it became. Just like it had before. There was something scratching, something trying – she thought – to get in. Then she felt it, a sharp pinch, sharp enough to make her catch her breath.

She stretched out her arm, but all she could see was a little brown smudge. She licked her thumb, and rubbed at it, then watched as more marks appeared, not much more than shadows at first. They darkened, blooming under her skin, resolving gradually into a series of purplish bruises, each one the size of a thumb print.