Girard and ViVi are special government agents known as "Right Arms" whose job is to seek and destroy people who have become infected. In their world, a weird virus that turns people into monsters has run rampant. The only way humanity can survive is to keep tight control on the infected to prevent the spread of the virus. If the virus' symptoms appear, the person must be disposed of. It's a tough world where even children must sometimes be killed to give humanity as a whole a chance to survive.