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.

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.

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.

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.

Monitoring paroled Jang Eun-hak, Dong-jin thwarts his renewed attempt at murder. A chase ensues, and Jang Eun-hak is eventually stopped by Kingfisher. This event prompts Tae-sung to resume writing articles about Kingfisher. Bo-na, despite her worries about these changes, decides to continue her own work.

Sergei, Bo-na's childhood friend and a mercenary from Russia, reappears, and the truth of The Gosiwon Case in Haegong-dong from four years ago begins to surface. Bo-na investigates Sergei's return to Korea. Meanwhile, Dong-jin learns that Jang Eun-hak, the culprit who murdered his parents, has been paroled.

After discharge, Tae-sung retreats to a secluded mountain lodge, where he coincidentally reunites with Bo-na. Heavy snow isolates them, and only the two stay at the lodge for a while. Sharing food and enduring the cold, they open their hearts and start to love. Meanwhile, released vicious criminals, fearing Kingfisher, try to return to prison.

Eight years ago, in World Cup-feverish Seoul, Bo-na's team holds a Meeting hidden. In the same building, chasing a pickpocket, Tae-sung attacked, collapsing. Bo-na finds him, calls 119. Four months later, Tae-sung awakens, meets Bo-na, falls for her. Bo-na, exhausted by her 16-year mission, plans to quit.

Bo-na and her team travel to a Gangwon Province casino to prepare for a Client Meeting. When their plans hit a snag, Bo-na must step in for the Meeting herself. Tae-sung, investigating a construction worker's death, heads to the casino where Bo-na is, while probing the construction company's Chairman. Meanwhile, suspicious individuals appear around Bo-na's Meeting target.

Bo-na, knowing today is Tae-sung's family's memorial day, takes a half-day off and leaves early. She does her best, but her mother-in-law's berating continues. Misunderstandings build as Tae-sung helps her after work, leading to an unexpected turn. Meanwhile, Tae-sung begins investigating the suspicious death of a construction worker.

As Bo-na keeps working, Yul starts whining, and Bo-na struggles with balancing childcare and work. Meanwhile, people are enraged by child sex offender Pyo Gyu-cheol's release after serving his sentence. Tae-sung meets Dong-jin who is tracking Pyo Gyu-cheol. Dong-jin believes Pyo Gyu-cheol could be Kingfisher's new target.

Hyun-nam tells Bo-na why she came to Durumi Electronics to find her. A Sales Team workshop takes place, and Bo-na spends time away from Tae-sung and Yul for the first time since her marriage. While enjoying an unexpectedly pleasant time, an unforeseen incident occurs at the accommodation.

Tae-sung and the police are surprised by Kingfisher's return and resolve to finally apprehend Kingfisher for good this time. Tae-sung seeks information from Detective Dong-jin, who previously pursued Kingfisher. Meanwhile, a new employee appears at Bo-na's company, seemingly harboring an unknown secret.

Bo-na, Tae-sung, and their four-year-old daughter Yul are a typical happy and harmonious family. After a three-year parental leave, Bo-na returns to work and successfully completes her duties from day one, defying concerns. Meanwhile, Tae-sung, covering a drug case, learns a serial killer who disappeared four years ago has returned.