With Earth seemingly entangled in endless war, it is hard to believe that the city of Olympus has attained a utopian society. This peaceful haven is made possible through its population made up predominantly of Bioroids—genetically engineered humans who can no longer reproduce on their own or experience extreme emotions. Deunan Knute is a legendary soldier who has been fighting in the wastelands for as long as she can remember. When Hitomi, a representative of Olympus, scouts her to become a part of their security force, Deunan is skeptical that there can truly be a place so calm. Proving her suspicions correct, Deunan soon learns of a dangerous plot that promises to plunge the city into chaos—by threatening the very existence of Bioroids. [Written by MAL Rewrite]

Deunan, a young female warrior, and Briareos, a veteran cyborg-soldier, are both partners and lovers. As members of E.S.W.A.T., the elite special forces serving Olympus, they are deployed whenever trouble strikes. The two fighters find their partnership tested in a new way by the arrival of a new member to their ranks—an experimental Bioroid named Tereus. (Source: ANN)

The story is set in autumn 2005, one year after Resident Evil 4 game took place. Due to an as of yet unexplained reason, zombies appear in a United States airport. The release of the zombies leads to danger of an outbreak.

The story revolves around the members of a private military company (PMC), and the uneasy tension between them and the regular military after a war that caused massive environmental destruction. (Source: Animekon)