In the year 2010A.D., Hyper Hurricanes born concurrently all over the world caused severe damage. Five billion people lost their lives, decreasing the world's population to 3 billion. Existing economies and militaries were wiped out. North America, Russia, and Northern Europe were frozen under solid ice; plains sank beneath seas; the world's geography was changed dramatically. Human civilisation enters a chaotic era.
The Japanese Government created special economic areas which have achieved a limited degree of recovery pursuant to the disaster. Powered Assist Technology, which had long been under study, played an important role in this recovery.
However, poverty flourished outside of these ecomomic zones and slums were widespread. The ruling class called themselves "Logos" and maintained their position by force of arms, introducing Powered Assist Technology into the military. They call the poor "Revenus", who are exiled to live outside the special economic areas.
Time has passed since then. The main characters, Katsuragi Jo and Tsurasawa Hitoshi, escape from "Phantom", a special force organised to watch Revenus and to suppress renegade elements of the Logos, taking with them a mysterious girl, Noto Saya. There are many who are interested in her, all with their own personal motives.