The game takes place in a future world where intelligent robots face an old enemy — the Virus Army. Many years ago the villains were defeated, but now they are back, obsessed with world domination. The severely damaged Guard Corps resorts to a last resort: it asks for help from the hero of the last war, the lone operative Kai, who knows how to harness the energy of a mysterious gravitational short circuit. Kai is the last hope of this world. The hero sets off on a journey through futuristic locations in an attempt to defeat the evil genius controlling the invaders.