Mad scientist Ralph Benson has been doing regeneration experiments on animals in his laboratory on Market Street in San Francisco. He convinces destitute R. B. Saunders to be his first human experiment for the sum of $1,000. When Saunders fails to come home that night, his wife contacts the police, who have been investigating the crazed chemist for some time. Saunders dies during the failed experiment, and Benson escapes just as the police arrive at his lab. He then shaves his beard and boards the passenger ship S.S. Paradise to New Zealand under the name "Graham." Knowing that policeman Crandall is on his trail, Benson knocks the officer out and throws him overboard. When passenger Patricia Wentworth is told of the murder, she relates the story to her aunt, Margaret Wentworth, who gossips the news across the ship. An arson fire soon breaks out, and as the ship begins to sink, the passengers are forced to board life boats. Margaret, Patricia, boxer Red Hogan, steward Jim, ship's officer Dwight and Benson are then shipwrecked together on a South Sea island. The natives, believing that "white men are evil spirits," plan to burn the survivors to death, but when Benson apparently brings Tanao, the wife of island chief Elan, back to life, the chemist is proclaimed "God of Life" and master of the island. He orders the lifeboat burned and tells his fellow passengers that he plans to keep them on the island as "subjects" for his experiments. On Tanao's advice, Benson decides to take "a white wife" and proposes to Patricia. Although she wants to refuse, the group convinces Patricia that she should accept the proposal as a delaying tactic. Benson then tells his "fiancée" that he plans to start his experiments with one of the three white men. The group plans to escape the island in a canoe, but Tanao learns of their scheme and warns Benson. Before they can leave, Benson orders Elan to capture Jim. When the others refuse to leave without Jim, Dwight takes the canoe himself, but he is discovered by native youth Barab and the two drown each other. Benson, as part of his experiments, imprisons Jim in a cave, but he agrees to release the steward as soon as Patricia marries him. A native wedding is performed, but Benson does not release Jim. Red and Margaret then convince the natives to force Benson to release and revive the steward. Afterward, Jim tells Margaret and Red that he was not actually dead, just in a state of "suspended animation," and that Tanao never died either, as she had merely suffered a heart attack. The three then find the drowned Barab and take him to Benson. Benson finally agrees to let the group leave the island, only to have Elan and the natives arrive and demand that Benson bring Barab back to life. When he is unable to do so, Elan orders Benson burned to death. Meanwhile, the four survivors sneak away from the village, just in time to signal a rescue plane. The plane whisks the four away, much to the delight of the pilots, who realize that they will receive a $10,000 reward from Sir Archibald, Margaret's Australian fiancé. During the flight back to civilization, Jim proposes to Patricia, who gladly accepts.