Yeo Ji-hoon tries to solve the mystery of old serial killer who has risen again. Nam Ye-ri is assigned to find a missing person. Baek Do-sik tries to uncover the cause of a supposed suicide. Could all their cases be linked?
After losing a trusted friend, a detective takes up his unfinished investigation. With his team's support, he uncovers a hidden trail of staged suicides - and a killer who preys on the vulnerable.
The owner of bar is murdered in a villa in Gapyeong. She was the queen of power who knew the fatal secrets that can shake the political world. The chief of the National Police Agency secretly asks Ji Hun to do the case.
As a new murder mirrors a serial killer case from seven years ago, painful memories resurface for the team. Now, they are determined to uncover why their leader, Yeo Ji-hoon, is hiding his connection to the original investigation.
As the team hunts for answers from a survivor of an old case, dark secrets about their leader and the police surface. But when one of their own disappears, they realize the killer may be closer - and more dangerous - than they feared.
