In a post-apocalyptic world overrun by mutated beasts known as Limbeekoon or Filth Monsters, humanity is forced to reside in large mobile cities called Regios and learn to wield special weapons called Dite, harnessing the power of Kei for self-defense. In the Academy City of Zuellni, Layfon Alseif hopes to begin a new life and forget his past. However, his past has drawn the attention of Karian Loss, the manipulative Student Council President, and Nina Antalk, a Military Arts student and Captain of the 17th Military Arts Platoon, who instantly recognizes his abilities and decides he is the perfect candidate to join her group. Yet, with a secret past that won’t leave him alone and unknown powers beyond the normal, Layfon just might not take it.