Huge monsters stalk the earth! Resembling the ancient legends of Oni, the monsters begin attacking the laboratory where Prof. Saotome developing the Getter Robo, a robot so powerful it overwhelms ordinary pilots! Prof. Saotome then locates three of the most dangerous men on the planet to draft as pilots: Ryoma the fighter, Hayato the bezerker and Benkei the giant!

The Getter Robo chases the enemy into a mysterious dark cloud in the sky. Ryoma finds himself alone in an alternative Heian-era Japan where modern technology has been applied to the ancient weapons.

Huge monsters stalk the earth! Resembling the ancient legends of Oni, the monsters begin attacking the laboratory where Prof. Saotome developing the Getter Robo, a robot so powerful it overwhelms ordinary pilots!