Gap Dong

From 1993 to 1996, in city of Iltan in Gyeonggi Province, a series of 9 murders continuously happened and police conclude that a killer nicknamed Gap Dong is behind these cases. However, detective Yang Cheol-gon suspected Ha Il-sik as the actual murderer, but Il-sik suicided before being arrested. 17 years later, Il-sik's son Moo-yeom becomes a police to prove his father's innocence. And he and Cheol-gon team up together to catch Gap Dong after he starts a similar series of incidents.