The Enid Blyton Adventure Series

Youngsters Jack and Lucy-Ann accept Philip's offer to spend the rest of the holidays at his clifftop home in Cornwall, where they meet a kind man who assists Philip's widowed mother, and Philip's sister; unbeknownst to them, a stranger is lurking.

Trapped in an old smugglers' tunnel, the boys find stairs leading to the cellar of Craggy Tops, an ancient cliffside home; mysterious stranger Bill offers the children a boat trip, but the suspicious kids try to find out what he really wants.

The day after Bill takes the children on a boat trip to the Island of Gloom, the kids find their way back to the island; there, while exploring a disused mine shaft, they stumble upon Jack printing counterfeit notes before he is held captive.

While camping in the garden near the end of the holidays, Jack convinces the other children to follow the call of an owl into the woods, where they find the broken wall of Woods Castle, see odd flickers and hear strange noises.

An unseen menace pursues the children on their latest look at Woods Castle, and in the frenzy to escape, Kiki gets lost and captured by a troubled young man; Dinah, meanwhile, presses Bill for details on his job, suspecting he is a secret agent.

The children enter Woods Castle through a turret window and continue their search for Kiki, who has been captured by a troubled young man; as they realise the place is home to strange happenings, they commit to finding answers to their questions.