The Great War of the past had polluted the surface to the point where it was difficult for living things to inhabit. Humanity gradually became exhausted and dwindled in number.
The remaining humans diverted the technology cultivated during the Great War and established huge city-states in the few areas with low pollution levels. People lived in the cities, steadily removing pollution both inside and outside, and gradually increased their population. As the population increased and cities were built in various locations, records of weapons, technical information, and other things from the Great War that hindered human reconstruction were sealed and erased. Hoping that people of later generations would not repeat the same mistakes.
Time passed, and it is now the modern era. An era when the Great War of the past is only spoken of as fragmented information. On the surface, it seems peaceful, but behind the scenes, there was no end to those who excavated and misused relics from the Great War based on the few remaining records.
There were guardians who cracked down on them and maintained the peace of the city. The Relic Countermeasures Division of the Bureau of Management──. Kouga, a young ace, and his partner, Ixus, continued to struggle day and night against criminals.