The Republic of San Magnolia is constantly being attacked by the Giadian Empire's army of unmanned drones known as Legion. After years of research, the Republic developed its own autonomous drones, turning the conflict into a war without casualties as claimed by the government. However, there is no such thing as a bloodless war. Beyond the walls protecting the 85 territories lies the "nonexistent" Eighty-Sixth Sector where young men and women are branded as Eighty-Six and stripped of their humanity as they pilot "unmanned" weapons into battle.