In 1986, in Hwaseong County, Gyeonggi Province, South Korea, a female corpse was found by the field in the hot summer. It had already smelled. Small town policeman Park (Song Kanghao) and Seoul detective Su (Kim Sang-kyung) took over the case. The only thing that could be confirmed was that the female corpse had been raped before her death. The serious lack of clues made the inexperienced Park and his partner Cao (Jin Luohe) rely on rough confession and sixth sense to force the suspect to confess several times. However, Su was objective and calm, and analyzed according to reason, eliminating the suspect several times. The police were constantly in conflict to prove and overturn, but innocent women were still brutally killed one after another, so they had to reach a consensus and work together. At this time, a young man (Park Hae-il) who was extremely consistent with the characteristics of the crime became the biggest suspect. The police locked him in with nervous nerves, and the DNA test report was also sent to the United States, but the case did not stop there.