In October 1986, two women are found raped and murdered on the outskirts of a small town. Local detective Park Doo-man, not having dealt with such a serious case before, is overwhelmed. Evidence is improperly collected, investigative methods are suspicious and modern
forensic technology is near non-existent. Park claims to be able to find suspects by eye contact. He questions a scarred
mentally handicapped boy, Baek Kwang-ho, after Park's girlfriend Seol-yung suggests the boy used to follow one of the victims around town. Park's partner Cho beats Baek and forces him to confess. Seo Tae-yoon, a detective from
Seoul with more scientific training in crime scene analysis, volunteers to assist the investigation. However, his and Park's methods clash. Seo determines Baek is not capable of committing the crimes. After closely studying the crime reports, he discovers the
decomposed remains of a third victim who had been killed earlier and finds that the killer struck on rainy nights and targeted women wearing red. Inspector Kwon, the police force's diligent but unrecognized female officer, observed that the same obscure song was requested on the local radio station on the night of each crime. Despite a stakeout, on the next rainy night, the killer murders a woman near a
gypsum mine. The next night, Park, Cho and Seo stake out the crime scene and interrupt a man masturbating. They apprehend him, but his improvised "confession" does not fit the details of the crime. He mentions a mysterious person who rises out of the outhouses at a local school; this fits with a similar story that two local schoolgirls told Seo on the night of the most recent murder. Seo investigates and finds the killer's only surviving victim, a traumatized woman living near the outhouses. She tells him details that exclude the man arrested at the crime scene. Park and Seo fight when the man is released, but when the killer strikes again, they agree to work together. Their investigation leads them to Hyeon-gyu, a handsome clerk at the mine who originated the song requests. Seo notes that Hyeon-gyu's hands are soft like the survivor's description and that he moved to the town around the time of the first murder, but otherwise has no concrete evidence. Listening to Baek's "confession" again, they realize that he had seen one of the murders as it occurred. They go to the restaurant run by his father, where they encounter a drunken Cho, who has been suspended for beating Hyeon-gyu. When other patrons mock the police for not solving the crime, Cho instigates a brawl. Baek hits Cho with a broken table leg, causing a rusty nail to puncture his leg, and runs off. Park and Seo chase him, but before they can learn what he knows, the frightened Baek stumbles in front of a passing train and is killed. The coroner discovers
semen in the latest victim, which could identify the culprit. But since South Korea is behind on the necessary scientific advancements, they are forced to send the sample to the United States to
compare it against Hyeon-gyu's. Meanwhile, the untreated wound in Cho's leg begins to develop
tetanus, forcing it to be amputated. On the next rainy night, Seo surveils Hyeon-gyu but dozes off and loses track of him. Park's girlfriend Seol-yung walks through a secluded wooden area, passing one of the schoolgirls Seo had befriended. The killer, watching from the trees, arbitrarily picks the schoolgirl and murders her. Enraged, Seo attacks Hyeon-gyu the next day. Park interrupts him with the results of the DNA test. They are inconclusive—Hyeon-gyu is neither confirmed nor excluded as a suspect. Seo tries to shoot Hyeon-gyu anyway, but Park stops him and Hyeon-gyu is allowed to leave. In 2003, the crimes remain unsolved. Park has married Seol-yung and is now a father and businessman. He passes by the first crime scene and stops at the spot where the first victim was found. A young girl tells him she saw a man in the exact place, who was reminiscing about something he had done there a long time ago. Park asks the girl what the man looks like, and she answers he looks very ordinary, so much to the point where she is unable to describe any outstanding details. Shaken, Park stares into the camera. ==Cast==