At Rocky Point Beach, the gang are all ready to have fun. But they are frightened off when the ghostly figure of a man in a diving suit materializes out of the surf. It soon vanishes, and the gang don't know what to make of it until later when they read of expensive yachts disappearing from the local marina. The newspaper quotes beach hermit Ebenezer Shark as blaming the disappearances on the Ghost of Captain Cutler, who died when his boat was rammed and sunk by just such a yacht. The gang interviews Shark, whose story leaves them incredulous, especially after Scooby-Doo tangles with Shark's own diving suit, which closely resembles the one that they saw on the beach. Fred Jones and Daphne Blake stay to watch Shark's movements while Velma Dinkley, Shaggy Rogers and Scooby visit Cutler's wid