A serial killer named Shin-Hyun gives himself up to police. He confesses to committing a series of particularly horrifying murders of exclusively female victims. He is imprisoned, awaiting the death sentence for his crimes. Yet the killings do not stop. They continue with all the same characteristics trademarks of the Shin-Hyun serial killings. The case is re-opened when two more bodies are discovered, both pregnant women. One is found in the city’s landfill site, and the other is horrifically murdered on a public bus. Detective Mi Yun (played by Yum Jung-Ah), and her newly appointed partner, Detective Kang (played by Ji Jin-Hee), are assigned to the case. Mi Yun and Kang have difficulty working with each other, as their personalities and working methods are constantly in conflict. Detective Kang goes about his new job buoyantly and enthusiastically. He follows a new suspect, Huh, and eventually catches him in the act of brutally murdering a woman in a crowded techno bar. Huh is taken into custody after Kang shoots and wounds him at the scene of the crime. Once again, the case seems to be solved with this spectacular arrest. Yet the murders continue in copy-cat style. The police desperately hunt for new leads. They start an in-depth investigation of a Doctor Chu, who is Shin-Hyun’s psychiatrist. But progress is frustrated when Dr Chu becomes a victim of the copy-cat killings herself. The murdered psychiatrist’s former boyfriend quickly becomes the prime suspect, a fanatical character named Choi. All the pieces in the mystery are finally starting to fit together, and the case seems almost resolved. But all efforts are suddenly frustrated once again, when Choi takes his own life. But still, the killings do not stop with his death. The case gets more complicated, when even the police themselves appear to become suspects in the murders. In unraveling this mystery, everyone involved is pushed to the limits of human understanding.