'Valhalla Sector 3' is a place where all crime is permitted. The only way to live a human life in this place is to become a top fighter in the 'Octagon,' kill others, and climb the ranks. Pai (파이), recognized for his excellent fighting skills, lives under the favor of an executive named Dexter and has never questioned the strangeness of the area. However, he accidentally encounters Oliver and, through him, becomes aware of the world of ordinary civilians...