Great Mazinger tai Getter Robo G: Kuuchuu Daigekitotsu

A mysterious alien force attacks the Getter team's base while Great Mazinger is unable to come to its aid. The assault destroys the original Getter Robo and costs Musashi his life, leaving Ryoma and Hayato grieving just as Earth faces an even greater attack.

A new machine, Getter Robo G, enters the battle with Benkei taking the vacant third seat. It soon joins Great Mazinger against Pikadron, an alien monster that grows stronger by absorbing their energy attacks. To win, the two super robots must abandon the tactics that feed their enemy and find a way to strip away its defense before another sacrifice is required.