As Nam-soon assists Hee-sik in his drug investigation, she has a run-in with the ominous Ryu Si-o. Ri Hwa-ja plots her revenge against Nam-soon.

Hee-sik witnesses the jarring effects of the drug when it strikes his team leader. Nam-soon's search for evidence garners attention from foes.

Geum-ju pays a strategic visit to Si-o, who has his own motives. During a birthday dinner, Nam-soon's family questions her growing kinship with Hee-sik.

Hee-sik begins to worry about Nam-soon after Si-o promotes her into his inner circle. Geum-ju probes deeper into a suspicious businessman.

Nam-soon pulls off a bold heist, putting Si-o on high alert. During a tense meeting, Geum-ju challenges Si-o — who in return begins plotting his revenge.

Geum-ju falls victim to Si-o's attack but proves she's one step ahead of him. As Nam-soon finally tracks down the drugs, her brother succumbs to them.

The drug infiltrates Nam-soon's family — prompting a search of the source and an antidote. A mourning Hee-sik furiously goes after Si-o's inner circle.

Si-o learns of Geum-ju's ruse and decides to expand his target. As the drug case becomes more intense, Hee-sik asks Nam-soon to move in with him.

To find out Nam-soon's identity, Si-o narrows down his search and goes after her family. Hee-sik faces harsh discipline after news of the drug goes wide.

Si-o vows revenge after discovering the truth about Nam-soon. While Hee-sik continues his investigation, Nam-soon and her family go on a trip to Busan.

Mourning the loss of Hwa-ja, Nam-soon directly challenges Si-o. But he refuses to lose, forcing her to endure incredible pain to save her adopted mother.

With Nam-soon on the brink of death — Hee-sik rushes to find an antidote. Nam-soon faces Si-o once again but witnesses a surprising turn.

Desperate for a reunion, Hwang Geum-ju seemingly finds her long-lost daughter. After discovering the truth, Gang Nam-soon prepares for her trip to Korea.

Nam-soon begins her search for her parents in Korea but experiences some roadblocks. Geum-ju suspects something's off with her newfound daughter.

The incident at the Han River puts a spotlight on Nam-soon. As Kang Hee-sik spends more time with Nam-soon, he connects the dots about her family.

After a dramatic reunion, Nam-soon becomes closer to her family. As Hee-sik continues to investigate a drug case, Nam-soon lends her assistance.