On a foggy night, two college students drown at the beach. While Si-mok investigates, Yeo-jin tracks down a man who was at the scene of the incident.

When Si-mok hears who’s gone missing, he starts gathering clues by going through phone records. Yeo-jin begins her own investigation.

Taken off the case, Si-mok and Yeo-jin return to their work on the police-prosecutor council. Tae-ha and Bit head to a sensitive meeting together.

Kang Won-chul weighs a dilemma, and fields questions from Si-mok about the deceased attorney. A young prosecutor has something to show Si-mok.

A suspect is arrested, but Dong-jae remains nowhere to be found. In the interrogation room, Si-mok and Yeo-jin try to draw out a confession.

While getting to the truth about the night of the attorney's death, Si-mok and Yeo-jin learn about the involvement of a mystery person.