The title character, Black Jack, is a physician who does not carry a medical license and operates outside the law, often travelling to hospitals worldwide to secretly assist terminal patients. Despite his medical prowess, he charges shockingly high fees which have earned him a reputation for callousness and greed. Unlike his more glamorous colleagues, he does not have a wife or children and is quite content with his simple lifestyle, although he does have a pet cat.
The game is played with five players who are dealt two cards each and placed in a circle. When a player has a pair of twos they may place them down, requiring the next player to pick up four cards. This continues until a player has no more cards to lay down and then they win the hand. The dealer has the option to skip a player or reverse the order of play. Jokers are rarely used but can be placed to alter the flow of the game.
During an encounter with a young street urchin who attacks and damages luxury cars, Black Jack recognizes the youth from a case he recently worked on in which a murderer called the Love Hotel Killer seduced and killed wealthy businessmen and then raped their wives. He advises the young man to stop dating the women and start working, but he ignores his advice and becomes addicted to cocaine. He also starts to develop a large carbuncle on his abdomen which resembles a human face.
One day, a crime boss hires Black Jack to treat his daughter, who has the hereditary heart disease Tetralogy of Fallot, at a refugee camp in Adentarl. The girl’s mother, Saranda, and her crime boss grandfather, Patterson, are desperate for a cure because their other child was a victim of gangster rival Kid Curry’s assassination attempt.
During a trip to S-city, Black Jack saves ice skater Rei Fujinami from an injury and she asks him to treat her friend Yumiko Inoue, who has a hematoma on her brain after a crash. She is a patient at the private hospital owned by Tokio Umetani, who prefers car racing to surgery. Jack agrees to examine her.