Based on a novel by Charles Nordhoff and James Norman Hall, a native sailor is punished under strict French law but escapes that and a typhoon.
On a south-sea island Governor Eugene De Laage (Raymond Massey) sentences a native to thirty days for stealing a canoe. Dr. Kersaint (Thomas Mitchell) complains and warns De Laage he will destroy himself. A schooner arrives, and first-mate Terangi (Jon Hall) swims ashore to Marama (Dorothy Lamour), daughter of Chief Mehevi (Al Kikume). De Laage greets his wife Germaine (Mary Astor) with a kiss. Terangi and Marama are wed in church and by native customs. During the feast they go off alone. Marama asks Terangi not to go or to take her. Captain Nagle (Jerome Cowan) finds Marama on board; but to keep Terangi from being demoted, she swims back.
At Tahiti a white man bullies Terangi, who socks him. The warden (John Carradine) arrests Terangi, and Captain Nagle complains to the governor about Terangi's six-month sentence. Terangi works on the road gang. He sees the ship, runs, dives off a cliff into the sea, and swims; but he can't catch the ship. Terangi gets another year. De Laage refuses to request Terangi's transfer to him. Germaine tells Marama, who is pregnant. Terangi tries to escape several times and now has 16 years. Dr. Kersaint pleads with De Laage, and Chief Mehevi says his people are unhappy; but De Laage says it is his duty to uphold the law. Terangi tries to hang himself but is cut down by a guard. Terangi hits the guard and escapes. He steals food, is seen, but swims and takes a small boat.
Natives celebrate Terangi's escape and De Laage learns that Terangi murdered the guard. Terangi survives a storm, kills a shark for food, and capsizes in another storm; but Father Paul (C. Aubrey Smith) and a boy rescue him. Terangi tells Paul he did not mean to kill, and Paul leaves him on land. Terangi returns to Marama after eight years and sees his daughter. Chief Mehevi tells them to go to the taboo island.
De Laage says something strange is in the air. Wind increases. De Laage catches a boy taking a canoe with food. Paul admits he picked up Terangi, and he protects the boy from De Laage's questioning. De Laage commandeers Nagle's schooner, and Dr. Kersaint warns De Laage again. Terangi in a boat takes Marama back to warn the people. Dr. Kersaint has to deliver the baby of Marama's sister. In the typhoon natives depart in boats. Paul, Germaine, and natives pray in church. Huts and buildings are destroyed, and trees are blown over. The church is damaged. Paul has Terangi take Germaine, and they make it to a large tree, as waves destroy the church. Dr. Kersaint and natives in a boat survive with the baby. De Laage returns from Nagle's ship. Terangi helps his family and Germaine get back to the island, says good-bye to Germaine, and sails off. De Laage embraces Germaine and sees Terangi's boat but lets them go.
Like Mutiny on the Bounty by the same novelists, this drama contrasts European punishment to Polynesian love of freedom from such constraints.