In the hustle and bustle of December 2199, as people eagerly await the upcoming year, a story unfolds. It revolves around Ragna the Bloodedge, an infamous rebel of the highest SS-class, whose bounty on his head is record-breaking. Rumours arise that he has arrived in Kagutsuchi, the 13th Hierarchical City. The enigmatic Ragna, known as the "Grim Reaper," has one goal: to dismantle the controlling system that governs the world. As a result, a diverse group of unmatched fighters flock to Kagutsuchi in pursuit of the hefty bounty.