Plot

A detective's son becomes a cop to catch Gap Dong, a killer whose case went cold. When his father died as a suspect, he refused to believe Gap Dong was dead. As new evidence emerges, both he and the original detective pursue the truth.

Ha Mu Yeon's father killed himself after becoming a suspect in the case of the Iltan killer, also known as Gap Dong. After the statue of limitations is up on the case, the original detective returns to continue his investigation. However, Moo-Yeom is now a detective and works to capture Gap Dong as well, refusing to believe that Gap Dong is dead. New evidence for Gap Dong appears in front of Moo-Yeom and he sets out to catch him once and for all.