Accused of murdering Dr. Saotome, the creator of Getter Robo, Ryoma Nagare finds himself imprisoned. When Dr. Saotome mysteriously returns and unleashes the powerful Shin Dragon, Ryoma reunites with his former allies to pilot Getter Robo and save humanity. Despite their efforts, a nuclear warhead strikes Shin Dragon, causing a catastrophic Getter Ray contamination that devastates most of the world's population. Thirteen years later, in a post-apocalyptic world overrun by Invaders, Shin Getter emerges from the nuclear ruins, piloted by the artificial human Go. With the support of the remnants of the Japanese military, Go, Kei, and Gai must pilot Shin Getter to eradicate the Invaders and secure mankind's survival.