Eccentic, elderly matron Patience Nodbury has a treasure map she's inherited from Black Hook, her pirate ancestor. To foil a mysterious thief who has tried to steal it, she divides it into four pieces, three of which she gives to fellow passengers booked to sail on the Suva Star, an old wooden sailing ship chartered for a treasure hunt on an offshore island. She is convinced that, according to family tradition, Black Hook will visit her before she dies. When the peg-legged "ghost" does just that, and she suffers a fatal heart attack, Charlie and Jimmy are faced with a boatload of red herrings including Bill Lydig, an escaped convict, Gene LaFarge, a certifiable neurotic accompanied by a personal psychiatrist, and the embittered Captain Kane, who was marooned on a deserted island by his ex-partner and vows revenge.