On the morning of their wedding, Kalu and Tuila romp joyously on their secluded South Pacific island. A pleasure yacht arrives, and the island's colonial governor invites the tourists to the solemn nuptials, where Kalu performs the "Forbidden Melody," a song which a man sings to his beloved only once in his life. In the jungle, Kalu meets Peggy, who arrived on the yacht, and commends her for her dancing skills, which she admirably displayed at the primitive wedding the night before. She asks him to sing the "Forbidden Melody," but he tells her that to do so would be taboo. A village child tells Tuila that Kalu was seen with a white woman in his arms, and Tuila finds Peggy to warn her to leave alone the innocent native boy, who is a diversion for Peggy at best. Kalu meets Peggy's entourage, including Bob Grant, a nightclub promoter who compliments him on his singing and offers him a contract to perform at his cabaret in San Francisco. Peggy later finds Kalu in the Thunder God's cave, where he pays obeisance. Peggy insists on entering the holy place despite Kalu's protests, and she convinces him that the Thunder God approves of their love. In San Francisco, Kalu sings his "Forbidden Melody" to jazz accompaniment. Peggy, already bored with her latest project of "civilizing the savage," flirts with a pro football player in the audience. At a party at Peggy's house, Kalu expresses his disappointment that he can never see her alone, and Peggy admits that she doesn't love him. Kalu, despondent, goes to a sleazy bar and gets drunk. When he hears his "Forbidden Melody," on the radio, he cries out and runs outside. Believing that he's heard Tuila's love call, he runs into the street, but the call was a siren from a fire engine and it strikes and kills him. Back on the island, the governor listens sadly to a recording of the dead prince singing an exotic song on the radio.