The Earth faces a threat of a kind never before seen--a force of seemingly unstoppable robots, the Zervire, march toward the planet's imminent destruction. Humanity's last hope comes in the form of Gravion, a mechanical secret weapon powered by gravity. In this second volume of episodes from the robot war anime television series, the Gran Knights continue to lead Gravion into battle against the Zervire invaders as they grow stronger and more lethal.