Theresa (Jane Russell) is the girlfriend of ship operator Johnny (Richard Egan), who teams up with perennial rainbow chaser Dominic (Gilbert Roland). They hunt for fabled treasure lost in an old Spanish galleon off the Cuban coast. Amid the threat of rapacious sharks and the hazards of underwater salvaging, the adventurers work against time. They must raise the gold from its ghostly grave before the rotting old ship's hull slips off the ledge where it has rested for centuries. If that weren't enough, the group must also outwit a local pirate.