The second season of Snowball Earth continues the action, mecha and science fiction TV series. The first season centered on Tetsuo, a shy boy whose only companion was a giant robot called Yukio. Together they fought as saviors against monsters from space. After the last battle, Tetsuo came home for the first time in a decade and found the planet buried in snow and ice, with the fate of humanity a mystery and his promise to Yukio still unfulfilled.