In Seoul, OH Jung-hyuk, a boxer, working occasionally as a debt collector, is preparing for a fight in the coming days. MOON Sang-min, a young and immature man, try to get money, feeling seriously threatened. WANG Sun-ho, a rich and arrogant young man, contacts his father, a powerful CEO of a big Korean company who categorically refuses to talk to him.

In the morning, OH Jung-hyuk, finishes a job for Tony but he will learn very bad news. MOON Sang-min, talks to the young woman at the karaoke but then in the street, he goes too far and Wang Sun-ho defends the young woman.

Jung-hyuk prepares for the fights he must do, supported by the memory of this young woman met at the cafe. The situation is serious. But what solutions are available to him to get out of it? Is this dead end the end of the road?

Sang-min finds himself trapped. The second deadline of the debt has come to an end. Jung-hyuk discovers Sang-min's troubles and decides to help him. The troubles continue for Jung-hyuk and his addiction reappears, reviving a memory that has haunted him for too long.

An unpleasant surprise awaits Jae-hwa as she returns home. Sang-min finally meets Sae-mi who asks him for help. Jung-hyuk learns from Mr. Park that he will have to fight soon to start paying down the debt.

For a paltry sum of money, Jung-hyuk injures himself slightly in the right hand. In tense relationship with his employers, he meets a young woman working in a cafe that intrigues him, reviving the images of a distant memory while Sang-min's problems are growing up.

Hyeon-jin already thought her new apartment building was eerie, and her next-door neighbors very strange-but when those neighbors end up murdered, things only take a turn for the stranger.

When a doctor learns a murderous secret from a sedated patient, he finds himself in the middle of an unsolved serial murder case. As dismembered bodies start showing up close to home, the doctor realizes he must solve the riddle before the killer discovers what he may know.

Byung-soo, a retired serial killer, lives a quiet life with his daughter Eun-hee, who has cared for him ever since his Alzheimer's diagnosis. When Eun-hee brings home her new boyfriend Tae-ju, Byung-soo realizes Tae-ju is a serial killer too. To save his daughter, Byung-soo must fight Tae-ju as well as his own mind.

A detective has been on the trail of a sadistic serial killer for years. As he dives headfirst into hunting the killer, they get into an accident and upon waking up the detective realizes his body has been switched with that of the murderer.