An English castle, secret passages, sliding doors, Army secrets, spies, and a fierce storm, mixed well with a group of lively children spending a summer in a hilly country village, results in a surprise holiday packed with adventure. Jack's interest in birds leads him to the deserted castle, but strange signals and curious doings hold him there. Mystery Island readers will be glad to meet again the kindly detective, Bill Smugs, and the personality parrot, Kiki. Miss Blyton is a favorite adventure story writer in England and boys and girls here will enjoy her fast moving tales. Good plot, and England in the vague present, without too much feeling for any particular time.