A Bona Fide Killer

Dong-jin recalls that Tae-sung's assailant and Kingfisher were in the same building in the past. He immediately proceeds with an interview with the assailant, during which he obtains a clue that Kingfisher might be a woman. Meanwhile, Bo-na catches her mother-in-law's Voice Phishing culprit and receives recognition from her mother-in-law. Although the family becomes harmonious, Tae-sung's anxiety steadily intensifies.

Bo-na's painful orphanage childhood surfaces, hinting at a past forged by violence and silence. Tae-sung faces a growing dilemma as doubts about someone close to him become harder to ignore. The task force closes in with a bold new lead, but an unseen hand seems to always stay one step ahead. What Tae-sung uncovers may destroy everything he loves.

A new murder case occurs, and it confuses the police, but they are sure that it was done by Kingfisher. Bo-na realizes she's framed, and the real culprit is Leila, her old colleague who is resentful toward Bo-na for past condemnation. The appearance of Leila makes Bo-na fearful for her family's safety.

Leila is identified as Kingfisher, but inconsistencies arise. Meanwhile, Bo-na realizes that Tae-sung knew about her identity as Kingfisher. He confesses his love, but she leaves. During her absence, Tae-sung tries to clear Kingfisher's name, shifting public opinion. He finds Bo-na, convinces her to reconcile, promising to learn her completely.