The development of nuclear fusion technology has led to the project Babylonia where humans would be able to colonize other worlds. During the same time, however, the Punishing Virus appeared in a vacuum chamber of an A-series zero-point reactor. Efforts to isolate the particles of the virus led to a leak which caused an explosion in the reactor that spread the contagious virus on a global scale. Due to this event, Babylonia became the only hub where unaffected humans existed for a long time.
In an effort to fight against the virus, humans created Constructs, a revolutionizing bionic technology that could withstand the virus intrusion by reconstructing the human body and mind through the Ego Ocean System. With this technology and appointed commandant, human seeks to fight back the virus to reclaim Earth as their own once again.