Stranger

As a teenager, prosecutor Hwang Si-mok underwent surgery to address an unusually developed brain, but the operation resulted in lasting and significant side effects.

A convict's heartfelt claim of innocence leads Si-mok to re-examine the CCTV footage, and during his investigation at Yongsan police station, he encounters officer Han Yeo-jin.

Si-mok agrees to participate in a live television broadcast to talk about Kang Jin-seob and vows publicly to uncover the truth within two months.

Rumors of Si-mok's violent tendencies spread, but he continues his investigation, growing increasingly wary of his protégé, Young Eun-su.

Si-mok investigates a recent murder by examining the victim's home for overlooked clues, with Yeo-jin assisting in the inquiry.

New evidence complicates the investigation, expanding the pool of potential suspects. Amid the growing uncertainty, some start to doubt whether Si-mok is truly innocent.

Si-mok and Yeo-jin collaborate secretly to track down Seo Dong-jae. When Dong-jae attempts to discard an item into the Han River, Yeo-jin intervenes to stop him.

Yeo-jin, angry over the police's treatment of Park Kyung-wan, attempts to challenge her superior but is intercepted by Si-mok, who cautions her about the potential repercussions.

Si-mok assembles a special investigations team comprising key lawyers and police officers, initiating their probe by focusing on Dong-jae as the initial lead.

Yeo-jin arranges for Ga-young to be moved to another hospital out of concern for her well-being. A nurse shares an unusual occurrence that adds to the growing sense of mystery.

Ga-young's mysterious convulsions are finally explained, shedding light on her condition. Meanwhile, Chang-jun's wife faces a travel restriction, adding to the tension. Woo-gyun turns to Chang-jun for assistance in resolving his personal troubles.

Si-mok and Yeo-jin uncover confusing clues in Kyung-wan's basement during their investigation. Meanwhile, Dong-jae returns to Chang-jun's office to retrieve his missing cell phone.

Si-mok returns home after a rooftop party and finds an intruder has left an item in his bedroom, prompting Yeo-jin and Geon to arrive quickly to investigate.

Yeo-jin begins to suspect a new perpetrator is responsible for the most recent murder. At the same time, Si-mok collapses shortly after leaving an autopsy.

Yeo-jin gathers evidence while Si-mok conducts an interrogation, leading to several key revelations. Although many mysteries are unraveled, the central issue remains unresolved.

Si-mok pursues what he believes to be the true murderer, leading him to a mysterious bag that holds significant consequences for several individuals.

Two college students die in a drowning incident at the beach on a foggy night. As Si-mok begins his investigation, Yeo-jin follows a lead by seeking out a man who was present at the scene.

Dong-jae presents several cases to Woo Tae-ha as police and prosecutors prepare for collaborative discussions on investigative authority.

Yeo-jin brings Geon into the team. While investigating the death of a police officer initially classified as a suicide, Si-mok and Dong-jae uncover evidence suggesting a more complex scenario.

Geon delivers a compelling argument during tense negotiations with prosecutors, while Lee Yeon-jae at Hanjo confronts an emerging conflict within the family.

Yeo-jin encounters Si-mok and Dong-jae during an interrogation at the prison. Meanwhile, Choi Bit tasks Yeo-jin with delivering a confidential file to a member of the National Assembly.

Si-mok is tasked with investigating what Yeo-jin knows about Bit's file, while Yeon-jae prepares for a crucial meeting ahead of a vote that will determine the future of her political position.

Si-mok initiates an investigation by examining phone records after learning of a missing person, while Yeo-jin also starts looking into the case independently.

Yeo-jin leads the investigation into Dong-jae's disappearance and uncovers a link to the murder of a police officer. Meanwhile, Si-mok visits Yeon-jae, raising new questions about his intentions.

A mysterious and unsettling photograph emerges, prompting an investigation into its origins and meaning. Authorities begin to suspect that a police officer may be involved in the case.

Si-mok investigates the puzzling death of a former prosecutor, uncovering inconsistencies that suggest the case may be more complex than it appears.

A witness emerges claiming to have seen the kidnapping and offers to identify the person responsible, potentially exposing flaws in the police investigation.

Si-mok and Yeo-jin are reassigned from the case and go back to their duties on the police-prosecutor council. Meanwhile, Tae-ha and Bit attend a confidential meeting together.

Kang Won-chul faces a difficult decision while responding to Si-mok's inquiries about a late attorney. Meanwhile, a young prosecutor approaches Si-mok with evidence related to the case.

A suspect is taken into custody, but Dong-jae continues to evade capture. Meanwhile, Si-mok and Yeo-jin attempt to secure a confession during the interrogation.

Si-mok and Yeo-jin uncover clues pointing to a mysterious individual's involvement in the attorney's death as they investigate the events of that night.

As details of a government cover-up emerge, Si-mok continues to investigate despite the police-prosecutor council being disbanded.