While out to sea, several Japanese merchant ships are mysteriously destroyed in the Pacific Ocean. Most of the crews are lost in the incidents, but a few manage to reach the nearby Odo Island before dyeing of radiation poisoning. An investigation is then launched to the island to uncover what could have caused the destruction of the vessels. Once there, the research team begins to hear of the local legends that speak of a giant monster that the natives have dubbed Godzilla. Exploring the surrounding area, the team and everyone in the village soon learn the truth, as the creature is quite real and is apparently a dinosaur awakened and mutated by nuclear tests.

Shortly afterwards, Godzilla leaves the vicinity of Odo Island and makes his way to Japan. Arriving in Tokyo, the monster manages to destroy the entire city as the attempts of the self defense force prove futile. Godzilla then retreats back into the water, leaving the city in ruins with thousands of people left dead or dying.

Witnessing the destruction, a scientist by the name of Daisuke Serizawa is reluctantly convinced by his fiance Emiko to use a weapon the doctor had created. Called the Oxygen Destroyer, the device is capable of splitting oxygen atoms into a fluid before disintegrating the molecules, allowing it to completely wipe out exposed forms of life. Destroying all of his notes to ensure the device is never recreated, the doctor insists upon being the one to use the Oxygen Destroyer against Godzilla. The plan ends up being a success, as Godzilla is disintegrated while underwater, but Serizawa also commits suicide to seal the device's fate and ensure it may never be created again.

This project was a concept proposed by The War in Space (1977) writer Ryuzo Nakanishi in June of 1978. Titled King of the Monsters: Rebirth of Godzilla, with the first portion of the title in English and the second in Japanese, the production was to be a remake of the original 1954 Godzilla film. The concept struck a cord with producer Tomoyuki Tanaka, as a more complete draft was commissioned. This second stage of production had both Nakanishi and writer Akira Murao, who did the Kill! (1968) screenplay, at work on developing the concept, and was submitted on October 22nd, 1978. Jun Fukuda was set to direct the movie, but for whatever reason the project never came to pass. Given the very late draft submission, it's also worth noting that this film was possibly going to be slated for a 1979 release instead, unless the project itself ran behind schedule early on and was axed for that reason.