Tetsuo Yabusame, a shy boy, once piloted the giant robot Yukio when huge beasts from beyond the galaxy attacked Earth in 2025. After eight years adrift in cold sleep, he woke to find the whole planet frozen under ice and snow, a Snowball Earth where he resolved to save the survivors who were left. This second season of the TV anime continues Tetsuo's fight on that frozen world after the events of the first season.