In a small Korean province in 1986, a series of brutal and seemingly random murders of young women shakes the rural community. The local police, led by the semi-competent but passionate Detective Park and the intense, violent Detective Cho, are unprepared for such crimes, as homicide is a rarity in these parts. They employ primitive methods of investigation, often relying on forced confessions and shamanic rituals rather than forensic evidence to find the perpetrator. Tensions rise as they struggle to understand the killer's modus operandi with the limited resources and knowledge at their disposal.

The situation escalates when a young detective from Seoul, Seo, is sent to assist the investigation. His urban sensibilities and methodical approach to crime-solving immediately clash with the local detectives' more rustic techniques. Seo insists on proper crime scene protocol and the importance of evidence over intuition. As more victims are discovered, it becomes a race against time to connect the dots. The detectives each grapple with their inadequacies and ethical boundaries; while the killer remains a shadow, always one step ahead, leaving the small-town cops in a perpetual state of anxiety and frustration.