Dr. O'Shay activates Astro by drawing all of the city's power and using it to jolt Astro to life. But the power surge overloads the Metro City Power System, turning Magnamite, the robotic power-controller, into a robotic menace. When Magnamite comes crashing across the city like a huge mechanical octopus, Astro must master his amazing powers quickly in order to save the city from the rampaging robot.