The alien Brainioids have invaded Earth, and they didn't come empty-handed. They brought Grav Spheres—self-contained gravitational environments housing the Brainium crystals they need, stolen from across the planet. Young inventor Chip and his mechanical companion Clawz, a robo-cat, must infiltrate each Grav Sphere and take control of it from the inside. The path runs upward through every captured sphere until it reaches the Mothership itself.