 In a driving rainstorm Gladys Doyle, secretary to novelist Mauvis Meade, struggles to the door of a remote cabin. A strange man in the cabin denies he has a package for Mauvis. He disappears into the night, and Gladys finds a dead man in the cabin. Mauvis arrives at home to find the place in a shambles, and shyster Gregory Dunkirk is glad that incriminating materials he gave Meade for her latest novel have been stolen. Gladys appears and tells her boss about the dead man, who turns out to be a Las Vegas gambler, Joseph Manley. Gladys consults Perry Mason and is arrested for murder. A scarf decorated with three mythical monkeys is found at the cabin, meant to implicate Mauvis in the crime. Other evidence points to Gladys. Perry must discover who is the framer, who was the man at the cabin, and what happened to the package.