Ever since she bit Father Christmas when she was six months old, it has been downhill all the way for Martha Bones. She is horrible to her baby brother Boris and elder sister Sally, and her parents are tearing their hair out. Far away from Earth, Martha s behaviour has come to the attention of the Interstellar Agency whose aim is to make bad children good. Fred, an Interstellar agent with a poor track record, is sent to Earth as Martha s guardian agent. His mission: to make Martha good. However, Martha has other ideas!