First Broadcast on 31st December 1978
Executive Producer James Gatwood
Produced by Sidney Hayers
Directed by Sidney Hayers
Adapted by Richard Sparks
Guest starring:
Michael Hinz, Sue Best, Frederick Von Thun, Rita Webb, Leon Eagles, Stephen Grief, Leslie Schofield & Chubby Oates.
Julian, Dick & Anne are holidaying in caravans. George has been sick and joins them later. Before she does the newspaper print an article on 2 missing scientists Pottersham and Terry Kane, who are believed to be traitors. It turns out that Pottersham has kidnapped Terry Kane and is selling their secrets to another country. Kane is being held captive in a castle near to where the Famous Five are staying and there is a fair nearby too.
Whilst using George's new binoculars Dick spots a face at the castle window. Believing it to be the msising scientist the Five set out to rescue him but end up being captured themselves, all except Anne who manages to escape and get help from the circus people.