This period swashbuckler film is based on the adventure novel Benjamin Blake by Edison Marshall, who also wrote The Vikings (1958). When his brother dies, scheming Arthur Blake (George Sanders) kidnaps his own nephew, Benjamin (played as a youth by Roddy McDowall and as an adult by Tyrone Power).
Arthur's purpose is to claim his brother's dukedom for himself. Put to work as a stable boy, Benjamin grows up and develops a crush on his own cousin Isabel (Frances Farmer). When Arthur discovers this, he mercilessly beats Benjamin, who runs away and sails to India on a cargo ship to make his fortune. In Polynesia, he and a friend, Caleb (John Carradine), jump ship and set up camp on a tropical island paradise. There, Benjamin and Caleb become rich mining pearls, while Benjamin falls in love with a native girl, Eve (Gene Tierney). Now that he has amassed wealth, however, Benjamin is determined to return to England and get his revenge on Uncle Arthur.