Sea Captain Ralls (John Wayne) deliberately sinks his ship, the Red Witch, owned by the East Indies Trading Company. The investigation that ensues is halted by Sidney (Luther Alder), the powerful head of the company. Ralls, with his partner, Sam Rosen (Gig Young), and mate, Ripper (Paul Fix), set out in an aged schooner for a South Sea Island lagoon, ostensibly to hunt for pearls. They are welcomed by Sidney. Sam soon becomes aware of the greed which motivates the lives of Ralls and the trader. Seven years earlier the men conspired to take a fortune in pearls from the natives of a Polynesian island. The men now plan to salvage the treasure aboard the sunken Red Witch. The resulting operation tests the courage and greed of all men involved.