'I heard a murder being planned.' Scarper Jack is a chimney-sweep's boy and he's actually in a chimney when he hears two voices planning a murder. He knows where and when it's going to happen -- but there's no way he can stop it. With the help of two unexpected friends -- a posh boy and a sewer rat of a girl -- he sets out to solve the mystery and track down the murderer. Only to find that it can be dangerous to know too much . . .