Second volume of the Japanese anime series. Earth is under attack from an alien life form with technology far in advance of mankind's. The only hope for humanity are the experiments of a mysterious scientist called the Sandman, who is attempting to build a machine, the Gravion, that will rival the engineering achievements of the distant past. Only four young teenagers have the ability to pilot this new craft, and together they must fight to secure Earth's freedom. In this volume, the team of Knights lead the Gravion into battle against the evil Zervives, as the Zervives become even more powerful.