The film starts with a nuclear bomb testing sight being built on an island, where the last living dinosaur, Gojirasaurus, has been in a coma underground for over 1000 centuries. Years later, a nuclear bomb is tested that awakens the Gojirasaurus awakens and is mutated. It emerges from several miles underground and rampages through the testing sight, killing several scientists. The Gojirasaurus walks into the water where it swims from the ruins of the testing sight. Later, underwater, some Japanese scientists are searching for the mutant Gojirasaurus. They give up after several hours of unsuccesful searching, and return to Tokyo. However, they see that the Gojirasaurus attacked while they were in the submarine. The Gojirasaurus is shot with missiles and driven back into the water, and begin