Set in the near future, a secret organization called , also known as , is bent on world domination. Using the electronics firm International Electronic Brains as a front to fund their activities, Tekkoryū builds an army of eight giant robots known as the , but Masaki Kihara, the scientist behind the Hakkeshū, betrays the Tekkoryū and steals , along with the embryo of the pilot genetically linked to the robot. He dies shortly after handing Zeorymer and the embryo to the Japanese government. Fifteen years later, Yuratei ascends to the throne as Empress of Tekkoryū and orders the recovery or destruction of Zeorymer before proceeding with her plans to conquer the world.
