1986 Gyunggi Province. The body of a young woman is found brutally raped and murdered. Two months later, a series of rapes and murders commences under similar circumstances. And in a country that had never known such crimes, the dark whispers about a serial murderer grow louder. A special task force is set up in the area, with two local detectives Park Doo-Man and Jo Young-Goo joined by a detective from Seoul who requested to be assigned to the case.
Bok-Soon (Kim Go-eun-I) runs a street stall while taking care of her younger sister. Bok-Soon may not be the brightest girl but what she lacks in intelligence, she makes up for in uncontrollable rage. She’s infamously known as the “psycho bitch” in her neighborhood. Bok-Soon’s relatively peaceful life with her sister is disrupted when they cross paths with a serial killer named Tae-Soo (Lee Min-ki). Tae-Soo kills Bok-Soon’s sister because she may have stumbled upon the truth of his murderous lifestyle. Bok-Soon’s rage consumes her completely, leading her to plot her revenge on Tae Soo.
While investigating the school files, the frightened teacher Mrs. Park startles and calls the young teacher Eun-young Hur, telling her that the deceased Jin-ju Jang is back. The line dies and Mrs. Park is attacked and killed by a ghost. On the next morning, the teenager Jae-yi Yoon waits for her friend Ji-oh Lim, who has the ability to call the spirits, and they begin a close friendship. The abusive and aggressive Mr. Oh, a.k.a. Mad Dog, is the substitute of Mrs. Park and prohibits Ji-oh to paint and compares the performances of the pretty So-young Park and the weird Jung-sook Kim, raising a barrier between the two former friends. Miss Hur misses her former friend Jin-ju, who committed suicide, and while trying to contact her, she discloses a dark secret about the past of her friend and Mrs. Park.
Kim Sun-woo is an enforcer and manager for a hotel owned by a cold, calculative crime boss, Kang who assigns Sun-Woo to a simple errand while he is away on a business trip; to shadow his young mistress, Heesoo, for fear that she may be cheating on him with another, younger man, with the mandate that he must kill them both if he discovers their affair.