Black Jack is a mysterious character who operates as an unlicensed doctor, and his past remains shrouded in mystery. Along with his loyal assistant, Pinoko, who has developed romantic feelings for him, he faces difficult medical problems that are often obscure, dangerous, or completely unfamiliar. Despite these challenges, he is able to save the vast majority of his patients thanks to his exceptional intelligence, although he is unable to help those who cannot afford his services. Black Jack has become a renowned figure, particularly within the scientific and medical communities. Though he relies on evidence to shape his beliefs as a man of science, he frequently finds himself amazed by the power of love and the forces of nature that defy his scientific understanding.