The story begins in a futuristic domed city called Romdeau, built to protect its citizens after a global ecological disaster. In this utopia, humans and AutoReivs (androids) coexist peacefully under a total management system. A series of murders committed by robots and AutoReivs infected with the Cogito virus (which causes them to become self-aware) begins to threaten the delicate balance of Romdeau's social order. Behind the scenes, the government has been conducting secret experiments on a mysterious humanoid life form called a "Proxy". The Proxy beings (described as God-like and Immortal) are believed to hold the key to the survival of mankind.