Han Dong-soo is a lawyer who makes a living out of his profession. He chooses a prisoner at random to visit and takes on a case. He is usually rational and reasonable, but deep down there is a dark side to him. Something drives him to cross the line and enter the world of evil. His younger half-brother is Han Beom Jae. Han Beom Jae works in a second-hand computer shop and also acts as a middleman for Han Dong-soo, bringing him clients. One day, Han Beom Jae notices that Han Dong-soo has changed since he brought him a case. The case concerns Seo Do Young, who is the second-in-command of a criminal organisation. He is a former baseball player and does not look like a typical gangster at all. Behind his handsome appearance, he hides a cruel and unpredictable madness.