The Ghost World sits right on top of the Real World, overlapping it at the edges. This is the way it has been for hundreds of years. But not until now has there been a story like that of Grey Arthur, an ordinary ghost, with no particular talent for haunting. Arthur's story begins on a park bench where the sound of young Tom's crying makes Arthur rouse himself. Never before has he heard a boy who so clearly needs help. And so Arthur's ghostly mission is sealed. An Invisible Friend - the perfect job for a ghost.