Where are the most influential people in Korea? Ironically, the answer is prison. Head of conglomerate, politicians, celebrities to penniless criminals are gathered. 60,000 criminals live in this lawless space where people are used to violence than law and balance on the account has more power. And a man appears at this chaos. This man has passed the physician licensure exam in highest score. He was from a regional medical school, but he managed to become the ace emergency medicine in Taekang Hospital, the best-known university hospital in Seoul. However, he was evicted from the hospital because of an incident with the son of the chairman. When he applied for the head of the infirmary at a prison, people regarded him as a saint or a madman. But he was neither of them. During 3 years of lurking, he learned an important lesson. For a man without any background, he needs strong personal connections that can lead him to success. And the place with every connection he needed was the infirmary of the prison. This story is not about desperate revenge or a medical drama in prison. It is the story of a man who wants to be successful. He will be using all sorts of methods that the corrupt people used in real life. Watching him returning evil deeds to them will give us peculiar pleasure.