When 17 vessels explode and sink near Odo Island, Professor Kyohei Yamane, his daughter Emiko and the Marine Hideto Ogata head to the island to investigate. Soon they witness a giant monster called Godzilla by the locals destroying the spot. Meanwhile Emiko meets her boyfriend, the secluded scientist Serizawa, and he makes she promise to keep a secret about his research with oxygen. She agrees and he discloses the lethal weapon the Oxygen Destroyer that he has developed. When Godzilla threatens Tokyo and other Japanese cities and the army and the navy are incapable to stop the monster, Emiko discloses Serizawa's secret to her lover Ogata. Now they have to convince Serizawa to use the Oxygen Destroyer to kill Godzilla.