Enid Blyton's first Famous Five novel adapted into an eight-part Children's Film Foundation serial. George (Rel Grainer), Julian (Richard Palmer), Dick (John Baily), Ann (Gillian Harrison) and their dog Tim (Dada) unearth a plot by antique shop owner Luke Undown (Robert Cawdron) to steal shipwrecked treasure from Kirrin Castle. With their customary zeal, the five set out to foil the dastardly plot and bring those responsible to book.