While searching for his missing brother, Ryota finds the criminal Yoshimura hiding on a yacht. With a few friends, they decide to set course for Leichi Island which happens to be in the hands of gangsters who are holding the natives of Infant Island captive. Ryota and his friends discover that not only near the island lies the monster Ebirah, the monster Godzilla is also on the island. A battle ensues between the two monsters.