Dr. Shizuma invented a revolutionary new form of renewable energy drive but had to pay a heavy price for his success in a catastrophic accident that the world wants to forget. 10 years later the secret organization Big Fire have obtained two of three mysterious Shizuma drives as part of their world domination plans. The third drive has however been taken by Dr. Shizuma who during his escape is saved by Giant Robo. A desperate struggle begins between the Giant Robo and Big Fire for the control of the last drive as Big Fire unleashes their ultimate weapon, the Eye of Volger.

An adolescent with the ability to control a looming war-golem becomes entangled in the Experts of Justice's fight against the infamous group Big Fire.

In the small town of Rockwell, Maine in October 1957, a giant metal machine befriends a nine-year-old boy and ultimately finds its humanity by unselfishly saving people from their own fears and prejudices.