The year is 1934. According to legend, the Polynesian island of Salutua disappeared after a fire god rose up from the volcano and drove away the natives. However, the eccentric Professor Sternberg believes that he's located the legendary island, after tending to a man found floating in the Pacific Ocean with giant animal bites on his body. An American millionaire, film producer Marshal Grover, funds an expedition to Salutua based on Sternberg's findings, apparently intending to use the island as a backdrop for a realistic monster movie. The expedition's ship, the Constitution, passes through what appears to be a freak atmospheric distortion which shrouds Salutua from the outside world, but is disabled by an underwater explosion as it enters the lagoon. The crew successfully beach the ship, and as they begin to conduct repairs, Grover's team sets off to explore the jungle. The flora and fauna on the island prove to be impossibly gigantic, but Grover's spoiled second wife, former starlet Nancy Norton, is terrified by the unnatural growth, and when she's attacked by a giant snake she flatly refuses to film anything on the island. Grover, however, refuses to take her away just yet. He has another reason for coming to Salutua—a motive connected to his beloved daughter Amelia, who lost an arm in the car crash which killed Grover's first wife.