Three convicts enroute to Tahiti are put to work at a children's leper hospital when their plane makes an unexpected stop on another island. There, Father Perreau is to get off and replace Father Doonan, who's been relieved of his duties by the cardinal. Once on the island, things get out of control when the volcano decides to erupt, and the Governor orders an evacuation. The convicts, priests and leper children are all on top of the island and have no sure way to get down and off to safety. All must work together if any are to survive.