Set in World War II, the film depicts the story of the real-life Japanese battleship, the Yamato, which is confronted in the Pacific Ocean by giant monsters, including the most fearsome of them all, Reigo.
When the Earth's ecosystem is disrupted due to global warming, a plethora of prehistoric sea monsters wage war on Japan. Led by the powerful Raiga, the monsters ravage the city of Asakusa.
Takeshi Hongo is a promising young man with a passion for motorcycle racing. However, his dreams are suddenly ruined when he gets kidnapped by Shocker, the evil secret organization planning to dominate the world. After being remodeled into a cyborg, Takeshi escapes and swears to protect the world from the inhuman monsters.
