- 1996, the (fictional) city of Iltan in Gyeonggi Province: A young girl gets brutally murdered by an unknown person on a dark night. As the city is gripped by a succession of serial killings, a total of nine murders within a twelve-kilometer radius since 1993, the police conclude that a man they've nicknamed "Gap-dong" is behind the crimes. But detective Yang Cheol-gon is convinced that the actual killer is Ha Il-sik, a resident of the town who is intellectually challenged. His attempt to arrest the suspect fails as Ha commits suicide to prove his innocence. His death inspires his son Moo-yeom to become a cop to clear his father's name and restore his honor.
- DirectorJo Soo-won
- WriterKwon Eum-mi
- Main castYoon Sang-hyun, Kim Min-jung, Sung Dong-il, Lee Joon
- Channel info.tvN
- Broadcasted2014.04.11 ~ 2014.06.21 (20 episodes)