The game is set in 2877, 800 years after the world's peacekeeping unions have collapsed. They are replaced with World Silent Security Service, a global world order to maintain the security on earth and in space. However, over time the role of the order is questioned, and the Reformist Faction rebel group sends three pilots in Laocorn assault robots to the WSSS' space station Daedalus in earth's orbit. Two are immediately destroyed, but the player gets to control the remaining robot.