In a world where monsters dominate vast regions known as territories, humanity faces a new threat when major cities are attacked by gigantic monsters emerging from everywhere.Amidst the chaos, Sief and his sister are separated and shot, with a final glimpse of his sister being affected in a strange way.After being struck by a blow that should have taken his life, Sief awakens in an unknown place, far from his home, only to witness a sinister omen in the sky that sent all the monsters in the surrounding area into a frenzy, initiating waves that would attack. more towns and cities. As humanity begins to face the waves, Sief decides to advance across territories in search of his sister after finding her city destroyed. Exploring ruined territories and torn cities, he clings to the hope of finding his sister alive.