Gisho Getter Robo Darkness

An incident eight years before the story's start involved explosions at the base of Mt. Asama, triggered by scientists, which led to a meltdown of Getter Ray energy affecting all of Japan. Exposure to this energy caused severe mutations in people worldwide, fusing them with both machinery and organic matter, earning them the name Idea. In response, the Getter Robo was developed by the organization GETTER. Three pilots—Ryo, Hayato, and Musashi—were chosen to operate the Getter Robo in order to fight against the Idea.