In a future age of unprecedented prosperity, driven by Dr. Shizuma's invention of the clean, renewable Shizuma Drive, humanity enjoys a golden era. However, this peace is threatened by Big Fire, a sinister organization seeking world domination. Opposing them is the International Police Organisation, which deploys a team of superhuman fighters and martial artists, as well as Daisaku Kusama—the guardian and pilot of the mighty Giant Robo.
When the IPO seizes an irregular Shizuma Drive vital to Big Fire's schemes, a fierce conflict erupts between the two forces. This battle tests Daisaku's determination, reveals the disturbing truth behind the Shizuma Drive's origins, and risks the destruction of human civilization.
Giant Robo is a character-driven adventure set in a retro-futuristic world, blending elements of opera, kung-fu cinema, wuxia tales, and classic mecha anime. Although it features characters originally created by manga artist Mitsuteru Yokoyama, the story stands on its own as a unique narrative.