In a world under the threat of Shocker, an enigmatic terrorist group stemming from the remnants of the Nazis, individuals are abducted and transformed into mutant cyborgs, then subjected to brainwashing to serve Shocker's agenda of global supremacy. Among these victims, Takeshi Hongo narrowly evades the last stage of brainwashing, emerging with his mind and values unscathed. Taking on the mantle of Kamen Rider, a superhero with a grasshopper motif, Hongo stands against Shocker's henchmen, determined to thwart their sinister plans.