Season 1

Akudo, the reckless juvenile delinquent son of the billionaire Nikla, crashes his sports car while driving dangerously around the streets of the city after a cloth from Davy, a young tailor, obscures his windscreen when he has to jump out of the way. Nikla searches the world for a surgeon to save his severely injured son, and eventually hires Black Jack for three billion. Jack advises Nikla that his son can only be saved by using the body parts of a donor, and Nikla has Davy arrested for causing the accident and forces him to be the donor. Two months after the operation, the bandages are removed and Nikla sees his son fully recovered, however a few days later he disappears from the hospital. It is revealed that Jack actually remodelled Davy's face to look like Akudo who had actually died from his injuries. Jack then changes Davy's face again and Jack gives him the money so that he and his mother can leave the country and never have to work again.

Black Jack and Pinoko are sitting in the Tom café where Osamu Tezuka sits drinking coffee and drawing manga. Pinoko drags Black Jack off to Sendai for an operation for the removal of a mole on a rich man's son. On the way, their car breaks down in the snow and they walked to a remote house inhabited by a talkative old woman. She is awaiting a visit from three of her four sons for her birthday, but they all notify her that they cannot come. However, Shiro, the fourth son arrives late, and explains to Jack that he was unwanted, became a delinquent and was disowned by his father, but has since become a doctor. Suddenly his mother falls with abdominal pain which Shiro suspects is long untreated appendicitis, but which Jack believes is "mobile cecum syndrome" and he operates on the old woman with Shiro assisting. They leave quietly the next morning while Shiro plans to stay and open a clinic in the village.

Dr. Wattman is the creator of the medical program, U-18 which uses computer technology to manage over 900 patients. However U-18 shuts down its operations, stating that it is ill and must be treated by Black Jack within 48 hours or it will terminate life support functions for the patients. Dr. Wattman argues that it is a machine which needs mechanical repair but the computer refuses to accept it. With only minutes to spare before the deadline, Jack arrives by helicopter, and agrees to operate for $10 million. After confirming his identity, U-18 agrees to switch its circuits off so that he can operate. Dr. Wattman tries to decommission U-18, but Jack refuses because it is his patient. After a successful operation, U-18 decides to retire, but Dr. Wattman realizes that the computer has become her daughter and they agree to run the hospital together.