It is around 6pm and the light has started to fade from the sky. I have been asked to a friends house to watch a film with him. I know that he will be home alone. Although I suspect him to try something, I feel perfectly comfortable with this arrangement. As I approach his house, I notice that it is all in darkness, except the hall. I knock at the door and wait for him to answer. He takes a while and I am about to give up...