An army captain is flying three misfit deserters home for a court martial when the plane has engine trouble and they crash-land in the ocean near an uncharted island. There they find a primitive society of cave women who routinely sacrifice virgins to appease The Great One, the top-dog dinosaur on the island. Mistaken for gods as part of a prophecy, the men must destroy The Great One or face death, but meanwhile they fall in love despite the advice of their Queen, who tries to dissuade them from being corrupted by the outsiders' ways.