Eddie hates staying with his cousins - so it looks set to be a really long summer. But then they visit the amazing caves at Wookey Hole and Eddie is entranced. Until he wanders off down a secret passage and gets lost in the dark. Underground, on his own, and nobody knows where he is...

Then someone steps out of the blackness to help him. A strange, pale girl called Gwerren who seems to treat the caves as a playground. Gwerren helps Eddie get out but she can never leave the caves herself. Is she a runaway? A ghost? Discovering the truth will end up changing Eddie's life for ever...

Tom Lawrence has appeared on TV in the Inspector Lynley Mysteries and Doctors, and on BBC radio in Like an Angel and Dead Perfect. His films include Stage Beauty, and among his stage credits are Biloxi Blues, Oliver Twist and Death in Venice.