I, the Executioner

The police raid an illegal gambling den led by Detective Seo Do-cheol, arresting several suspects and confiscating evidence. The raid sets off a broader investigation as authorities connect the den to a wider network of violent crimes. This action establishes the case's tone of relentless pursuit.

An online video surfaces showing a masked killer executing a disgraced art professor, sending shockwaves through the city. The clip cements Haechi as a vigilante figure and intensifies the public debate over justice.

Investigators realize each victim was a past offender who had escaped justice, and they are killed in the same way they harmed others. The pattern suggests a serial killer who chooses victims to mirror their previous crimes.

Editor Justice, a popular YouTuber, begins covering the murders and dubs the killer Haechi, portraying the case as exposing a flawed legal system. Public support grows for the vigilante, complicating the police's pursuit of the killer.

News reports warn that ex-convict Jeon Seok-woo, who killed a pregnant woman in a drunk-driving incident, may be the killer's next target. Police relocate him to a safe house for protection as the case tightens.

Rookie officer Park Sun-woo proves himself by securing the safe house and showing unusual restraint and politeness under pressure. His calm competence makes investigators take notice and sparks suspicion about his true role in the case.

Jeon Seok-woo escapes from the safe house and is later found dead, heightening the stakes and suggesting internal sabotage or a more complex plot. The incident shocks the team and forces a reevaluation of security protocols.

A staged confrontation on a live stream at Namsan goes disastrously wrong when Sun-woo assaults a man he wrongly believes to be Haechi. The target turns out to be an actor hired by Editor Justice for content, not the killer. The incident fuels internal suspicion toward Sun-woo.

Min Kang-hoon, a traumatized former soldier, emerges as a new suspect after a violent pursuit involving a biker gang. A rooftop fight follows, ending with Kang-hoon nearly killed before police intervene.

Forensic evidence points to the possibility that Jeon was killed by a leg-based choking technique, the same move Seo recalls seeing Sun-woo use. Seo begins to suspect Sun-woo might be Haechi embedded in his own team.

Sun-woo kidnaps Editor Justice and rigs a trap, forcing Seo to choose between saving his own son or another innocent woman. The tense confrontation underscores how personal the stakes have become.

Seo's team rescues his son just in time and confronts Sun-woo in a brutal final showdown. Sun-woo nearly kills Seo, but Seo manages to survive and insists he must face justice for his actions.

In the quiet aftermath, Seo shares a moment with his son, acknowledging his past emotional absence and vowing to protect his family. The scene offers a human counterbalance to the violence that defined the case.

A post-credits scene reveals that Sun-woo has escaped while being transported to prison, leaving an opening for future consequences. The escape hints at deeper schemes still at play.