In this school fantasy story set in the distant future, creatures contaminated by pollution have overtaken the land, forcing humanity to live in isolated mobile cities called Regios. One such city named Czerni is a self-contained school in which freshman Reifon Aruseifu has just enrolled. Reifon reluctantly joins the 17th Martial Arts Studies Unit led by the third-year student Nina Antōku and embarks on a series of adventures.

It is an original side story that focuses more on Nina.