A thousand years ago in an alternate dimension that is somehow different than ours, a holy war was taken in the human realm on the surface of the earth that lasted a decade. A giant dragon appeared out of nowhere and put an end to the war by sealing away the leader of the god, demon and fallen angel races.
A thousand years had passed since the war, but the humanity has yet achieved an eternal peace. Remnants of the three races which had lost their leader are still appearing in the human realm from time to time with an aim of seeking a way to unseal their king.
ZoNe, a special organization was created to encounter such situation. Humans with special ability are scouted and recruited as a unit of anti-forces called The Excel.
Will the three races be able to resurrect their kings or The Excel will be able to prevent it? Meanwhile, as they’re battling against the three races, the secret behind of holy war starts to surface.