Sheena and I were good friends at school, but we lost touch. I hadn’t seen her for about ten years when one day I went into a bookshop and there she was behind the counter. She was reading, looking slightly bored. Her hair was longer than ever. I watched her for a while, excited with the sensation of observing unobserved, and wondering whether I should slip out again or say something before she realised I was standing there. Just then she shifted from one foot to the other, and I spoke.