Stranger

As a teen, prosecutor Hwang Si-mok received surgical treatment for his abnormally developed brain, but the procedure left behind serious side effects.

The convict's strong plea for his innocence prompts Si-mok to review the CCTV clip. At the Yongsan police station, he runs into officer Han Yeo-jin.

Si-mok volunteers to appear on live national TV to discuss Kang Jin-seob. He also makes a bold promise to find the culprit within two months.

Rumors quickly spread about Si-mok's violent nature. Regardless, he persists in his investigation. He finds his mentee, Young Eun-su, suspicious.

Si-mok, puzzled by the details of the most recent murder case, visits the victim's home to seek more clues. Yeo-jin joins him in the investigation.

New pieces of evidence only increase the list of possible suspects. In the midst of the confusion, a few begin to question Si-mok's innocence.

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.

Police and prosecutors each prepare members for joint discussions on investigative authority. Dong-jae brings Woo Tae-ha some cases of interest.

Yeo-jin recruits Geon. Digging into a policeman's death ruled as suicide, Si-mok and Dong-jae find signs that point toward a different story.

In a heated first session with prosecutors, Geon makes a pointed argument. At Hanjo, Lee Yeon-jae faces an oncoming family power struggle.

At the prison to interrogate an inmate, Yeo-jin runs into Si-mok and Dong-jae. Choi Bit has Yeo-jin deliver a mysterious file to an assemblyman.

Si-mok is ordered to find out what Yeo-jin knows about Bit's file. Ahead of a vote on the fate of her seat, Yeon-jae sets up an important meeting.