Great Mazinger vs. Getter Robo

When a UFO delivers a metal-eating monster to the heart of Japan, Getter Robo and Mazinger Z are sent into action to confront the alien menace. Fighting separately, the space monster's metal-eating and acid-spitting abilities prove overwhelming for Japan's super-robot forces—only their combined might has any chance of defeating it. Yet with Mazinger Z damaged, can Getter Robo hold off the monster long enough for its comrade to be repaired? And even together, can they defeat the monster before all of Japan is destroyed?