The Xilien have invaded Earth. Unleashing monsters and kaiju on the planet through a spacetime vortex, creatures of all generations attack humanity. Beginning their assault in Tokyo, Ebirah, Biollante, Megaguirus and other mind controlled kaiju assault the Earth. Mobilizing, a defense force fights back against the invaders using advanced weaponry. Pushing back the alien forces, the Xilien set their scopes on London, Sydney, Arizona and New York while their quest to secure the water on planet Earth is unveiled.