Takeshi Hongo is a promising young man with a passion for motorcycle racing. However, his dreams are suddenly ruined when he gets kidnapped by Shocker, the evil secret organization planning to dominate the world. After being remodeled into a cyborg, Takeshi escapes and swears to protect the world from the inhuman monsters.
With the help of Interpol Agent Makoto Arai, the newly-powered Gorou Watari/Sanagiman/Inazuman continues his adventures, this time against the nazi-like Desper Army led by Fuehrer Geisel.
A grasshopper-like, motorcycle-riding cyborg (joined by another one later in the show) fights the evil organization that transformed him for their evil deeds.
