Seven-year-old Lucy Gibson can barely contain her excitement when she learns that the funfair has come to town and Matt, her mother's new boyfriend, has agreed to take her. Despite her slight uneasiness in Matt's company and her upset over her parent's split, she readily goes off with him one evening, as excited as only a young innocent child can be. The next morning, Chief Superintendent Lambert briefs DS Bert Hook and DS Ruth David on the disappearance of a young seven-year-old local girl from a funfair the previous evening. On questioning her distraught mother, it appears that Lucy has vanished into thin air and so begins an intense investigation, racing against time, to discover who took the young girl - and to prevent more children from going missing before it's too late . . .