Snowball Earth

With only his colossal mechanical robot companion, Yukio, as his sole possession, the cautious Tetsuo announced his intention to make a friend. The two valiantly fought extraterrestrial monsters, earning the moniker of “saviors.” However, after a decade of absence, Tetsuo was shocked to find Earth transformed into the hazardous Snowball Earth. What had befallen humanity during his absence? Could he keep his promise to Yukio and protect them?