The worst of them will stay with you... forever.

During the late 1980s, two detectives in rural South Korea attempt to solve a series of gruesome rape-and-murders of young women that leave the community terrified using limited resources and outdated methods. But when the murderer strikes several more times with the same pattern, the detectives realize that they are chasing the country's first documented serial killer. They then attempt to piece together the clues in this thriller based on true events.