Genial inventor Doctor Komiodji saved a mortally wounded boy named Jiro by replacing his body with an artificial one and giving him the name Kikaider. Capable of genuine emotions, Kikaider can understand the difference between good and evil and make a conscious choice. The main task of the android is to protect Masaru and Mitsuko, the professor's children, from the evil Doctor Gil, who dreams of recruiting Jiro into his army and conquering the world.