In the year 200X, Doctor Randow attacks humanity with his mechanical monsters in order to conquer the world. Regular weapons don't seem to work against the Metal Beasts. To combat him, Japan's Defense Agency request the cooperation of NISAR, the Japan International Aerospace Corporation, which has developed a super robot, the Getter Robot. Despite being a robot developed for exploration, not for combat, [Ichimonji Gou] (the pilot), with the help of [Daidou Gai] and Tachibana Shinichi faces the Metal Beasts with success. As the dangers increase, Getter Robot gets improved into a transforming combat machine piloted by Gou, Gai and Shou (Shinichi's sister).