Black Jack is an "unregistered" doctor with a murky, mysterious past. He works alongside his young assistant Pinoko (who harbors a massive crush on the doctor), handling medical cases that are obscure, strange, dangerous, or entirely unknown. However, he is a genius capable of saving almost any patient's life (provided they have the money for it, that is), and he is known to many around the world, particularly within the fields of medicine and science. He is a man of science himself, skeptical until he has seen evidence, yet he is often surprised by love and nature overpowering the science upon which he bases his life.