After his superior is arrested, Kang Tae-ju is reassigned and returns to his hometown of Kangseong following a demotion. On his first day working at the local office, he learns from his coworkers that a former convict connected to one of his past cases has been brutally assaulted.

Following a tense and uneasy reunion with Si-young, Tae-ju throws himself back into the hunt for the serial killer. As the investigation intensifies, a determined reporter named Ji-won becomes involved, joining the effort to track down the murderer.

After Tae-ju assaults the county governor's nephew in retaliation for Soon-young's attack, he faces the serious threat of losing his position. Meanwhile, a victim's testimony leads him to a troubling discovery

Reeling from the death of Min-ji, who had placed her trust in him, Tae-ju seeks out Si-young and proposes that they work together to capture the serial killer. His return sparks tension and debate among his colleagues, but Tae-ju remains single-minded, determined to continue the hunt.

As suspicion tightens around Gi-beom, evidence seems to seal his guilt. However, more evidence proves to contradict the timeline. As Tae-ju digs deeper, suspicion shifts toward someone with close access.

Doubt grows over Lee Gi-beom's guilt as his confession is exposed as coerced through illegal detention and abuse. Tae-ju confronts corruption within the investigation while Ji-won uncovers new leads.

Doubts grow over Lee Gi-beom's confession as Tae-ju uncovers corruption, illegal detention, and a cover-up. Suspicion shifts to Im Seok-man, while new evidence reignites the hunt for the real serial killer.

Im Seok-man is forced into a false confession during a police reenactment, while authorities declare the case solved. Tae-ju grows suspicious and starts uncovering corruption behind the investigation and Gi-beom's death.

As buried secrets resurface, Tae-ju begins uncovering a terrifying truth behind the serial killer case everyone believed was solved. A hidden child, suspicious police involvement, and growing distrust push the investigation into darker territory, forcing the team to question everything they thought they knew.

Tae-ju gets closer to exposing the truth as shocking connections between past victims and the police begin to surface. Trust inside the team starts to crack, while a dangerous suspect makes a bold move that puts everyone at risk. With time running out, the investigation spirals toward an explosive confrontation.