In a Port Moresby, New Guinea bar, Nick Brandon, a pilot for a gold mining company, confers secretly with fellow American Gerald "Jumbo" Johnson about a gold theft they are planning. Then, while Brandon enjoys a drink with Katherine Shelley, an unhappy, drifting alcoholic, a stunning schooner pulls into port, catching everyone's eye. Upon disembarking from the schooner, called The Seeker, owner Steve Singleton is approached by Jumbo, who suggests they go into the pearl diving business together. While pondering the offer, Steve runs into Brandon, an acquaintance from the war, and without explanation, slugs him in front of Katherine. Steve then accepts Jumbo's deal, for which he is to supply the boat, while Jumbo provides the legal papers, equipment and manpower. That night, Katherine drops by The Seeker on a pretext and admits to Steve that she loves the freedom implicit in boats and yearns to run away on one. Katherine begs Steve to take her with him and spends a romantic night on the boat. The next morning, Jumbo arrives with the papers, crew and equipment, and Steve says goodbye to Katherine and heads out to sea. Two weeks later, Steve and his men are still searching for their first pearl when an Australian naval inspector boards the boat. After the inspector declares Steve's papers forgeries, Steve is arrested and his boat impounded. Steve serves a brief sentence, but learns upon his release that The Seeker has been sold at auction to Jumbo. Determined to reclaim his boat, Steve heads for Port Moresby and boards a foundering vessel, The Susan , manned by two English rogues, Sir Cecil Daubrey and Algernon "Mousey" Sykes. Steve fixes the boat's engine and, impressed by his skills, Cecil asks him to assume captainship, as the original skipper died at sea. When Cecil and Mousey are brought in for questioning by Australian authorities, curious about how the captain met his death, Steve chats with magistrate Sir David, who tells him that Katherine and Brandon flew off together two weeks before and have not been heard from since. Presuming that both were killed in a crash, Sir David also tells Steve that Katherine's husband died during the war and she started drinking out of grief. Later, after he and Mousey are released, Cecil confides in Steve that he knows that Brandon's amphibious plane was carrying ten million dollars in gold bullion and has surmised where in the jungle terrain it might have gone down. Once Steve hears that Jumbo is also pursuing the gold, he accepts Cecil's captainship and takes his devoted helper Bumidai along. As The Susan nears the river-fed lake, Cecil and Mousey plot to betray both the government, which is legally entitled to two-thirds of the gold, and Steve. Before they can execute their plan, however, they see Brandon's dead body in the water and spear-carrying headhunters on the shore. After Steve spots an imprisoned Katherine in the tribe's village, he convinces Cecil and Mousey to help him rescue her, reminding them that she knows where the plane is. Steve frees Katherine, but Bumidai is killed while they are fleeing the village. On The Susan , Katherine thanks Steve for saving her, and the two kiss. The next day, Steve sees The Seeker and swims to board it. Though startled by Steve's appearance, Jumbo agrees to join forces with him. After boarding The Seeker with the others, Katherine describes the plane crash and explains that Brandon became Steve's enemy during the war after he left Steve to die in a burning plane. When she is asked by the men to reveal the gold's location, however, she denounces Steve as a cold opportunist and starts drinking again. Once drunk, Katherine guides the men to the sunken plane, and Jumbo and Steve, who is planning to buy back The Seeker with his share, begin diving for the bullion. As they are retrieving the last two bricks, the scheming Cecil and Mousey drop a net on them. Using his knife, Steve cuts his way out, then saves Jumbo from drowning. Later, as they are headed back to Port Moresby, Steve convinces Mousey and Cecil that each has double-crossed the other. Mousey attacks Cecil and during the ensuing fight, is thrown into the river, where crocodiles devour him. The boat then is attacked by the headhunters, who kill Cecil with their spears and fatally wound Jumbo before Steve can steer the boat to safety. With his dying breath, Jumbo apologizes to Steve and encourages him to stick with Katherine. Later, the newly married Katherine and Steve sail off on The Seeker , ready to face the future together.