Lots of children find it difficult to sleep on Christmas Eve, usually because they are excited about the presents that Father Christmas is going to bring. But Pip Parker is not excited, she's scared. Every night for a week she's been lying awake watching the horrible skull shape gleaming from her bedroom wall. What is it? Why is it haunting him? When will it go away? The answer turns out to be reassuringly simple – the shape is caused by the light from the landing passing through the keyhole and casting a “skull” shadow on the wall.