After his last battle, Tetsuo returns to Earth for the first time in ten years, but instead of the Earth he knew, what awaits him is a foreign new landscape: one that is completely engulfed in snow and ice: a ‘Snowball Earth’! What has become of the human race? What was the actual outcome of humanity’s battle with the monsters? And will Tetsuo be able to fulfill the promise he made to Yukio?