Three children go missing and police organise a massive search of the town of Dudleigh and surrounding areas. A call from a security officer at Russington Hospital immediately has several Detectives heading for the Accident & Emergency Department. All three missing children have somehow been returned to the Hospital. No-one sees or hears anything; it's as though the children appeared out of the sky. The Doctor is puzzled - the children are in excellent health but are refusing to talk to anyone, not even their own parents. Local detectives are baffled. Where have they been? What have they been doing? Why won't they talk? All questions the police want answered. And urgently. When another young girl goes missing her 10 year old brother Harry and his three friends, Stan and identical twins Polly and Lily, are determined to find her and solve the mystery once and for all. Will they solve the mystery before the Police? Can they find out the 'Where's and the What's' and also the 'Why's and the How's?