The girl with no name lived a life of drudgery a prisoner of Sir Clifford and Lady Manning, who kept a wild-life park. Her only friend was Tomb, a chimp. When Delia Greenwood, a newcomer to the area, had visited the house with her father, a blacksmith, to shoe the Mannings’ horses, the girl tried to pass her message which was intercepted by Sir Clifford.
Kim Foley had made friends with a strange girl, Anne Marie, who was kept prisoner in her room at Sandley Manor, known to the locals as Misty Manor. Kim defied Anne Marie’s cousin Beth who had placed a ban placed on her visits.
Rambling over the wild cliffs near the Scottish fishing village where she lives, Aileen Andrews, sees a pigeon shot down. On its leg she finds a message saying that her brother, Hector, who was presumed lost at sea, is a prisoner on Misty Island. Dirk, the man who, shot the pigeon down, discovers that Aileen has read the message and forces her back to the motorboat in which his companion, Angus, is waiting to take him back to Misty Island.