Takeshi Hongo is a man of extraordinary intellect, but his promising future is about to be snuffed out by an evil secret society known as Shocker. Reinvented against his will and transformed into a powerful experimental cyborg, Hongo will forever be known as Masked Rider the First. He manages to regain his self-awareness and realizes he is being controlled by evil.

Shocker brands Hongo as a traitor and is prepared to do everything in their power to destroy him, even creating a new, nearly identical cyborg named Masked Rider the Second. However, their powers are too evenly matched and Shocker decides that both Masked Riders must die in order to usher in their plans of total world dominance.