"the Famous Five" Five On A Secret Trail(1978) -

They soon discover a gang of criminals is using the cottage to search for a hidden secret tunnel. This tunnel reportedly contains a "precious blueprint" that the criminals are desperate to recover.

The plot follows the children—Julian, Dick, Anne, George—and their dog Timmy as they go camping near a derelict, ruined cottage on the moorland near Kirrin. "The Famous Five" Five on a Secret Trail(1978)

The group meets a young boy, Guy Lawdler, who is involved in a local archaeological dig. They soon discover a gang of criminals is

was the eleventh episode of the first season of The Famous Five television series, premiering on September 18, 1978 , on ITV . This episode, like the rest of the Southern Television series, updated Enid Blyton's 1956 novel with a contemporary late-1970s aesthetic, featuring the children in modern attire like jeans and polo shirts. Episode Summary The group meets a young boy, Guy Lawdler,

The adventure begins when Anne and George witness strange flashing lights coming from the abandoned cottage at night.

Some viewers criticized the 1978 adaptation for its use of "dark filters" during nighttime scenes, which can make the footage difficult to see even in remastered versions.

This series was recorded on film rather than video tape, making it one of the most expensive children’s shows produced at that time.