Seok-joo joins the police on the morning of the Killing Vote. The police are dispatched to rescue Captain Oh, who was designated as the victim, and they are one step closer to the identity of Gaetal.

8 years ago, the case between Mu-chan and Seok-joo is revealed. The story of Seok-joo's young daughter dying and Seok-joo killing the culprit himself. And who the accomplice of the dead criminal is revealed.