The genius robotics professor Dr. Komyoji has created Kikaider, a humanoid robot gifted with a "conscience circuit" enabling Kikaider to simulate real emotions and distinguish between right and wrong. "Jiro", as he is called by Dr. Komyoji's children Mitsuko and Masaru, finds himself struggling to protect Mitsuko and Masaru from the evil Dr. Gill and his androids, and also to understand his own conflicted emotions. Is the conscience circuit a blessing or a curse?