A teenage skipper and his friends sail from a busy harbor on a small, weathered sloop and embark on a series of coastal adventures. Their voyages include salvage and treasure hunts, exploration of Nobody’s Island, encounters with a mysterious man with a glass eye, and a sunken wreck that leads to digging, clues and rival claims. Storms, a marooning and daring lifeboat rescues test their seamanship and resourcefulness, while episodes of humor and invention—trained clams among them—combine with investigations and reconciliations to bring the youthful expedition to a final recovery of treasure and resolution of disputes.