Tae-soo gets a call from his wife, who died one year ago. As Tae-soo learns about Ji-soo's shocking secret, Joon-tae becomes increasingly apprehensive as the investigation progresses. Meanwhile, Ha-bin, who believes her mother is a murderer, begins to dig deeper into her mother's past as an unidentified man follows her from behind.

A man who claims to be Song Min-a's dad appears before Ha-bin and demands to know about her relationship with Choi Young-min. Ha-bin learns from him that Tae-soo helped Young-min escape from the police. The police raid Young-min's place and take all the kids for questioning. Ha-bin finds where Young-min is and hears who killed Lee Soo-hyun and why.

At the scene of Choi Young-min's murder, a woman's necklace is found. Knowing it belonged to his wife, Tae-soo worries it might put Ha-bin at the scene. Later, Tae-soo visits Park Joon-tae after learning that Joon-tae personally knew Choi Min-ah, and the man claiming to be Min-ah's father shows up at Sung-hee's place to question her about the day Min-ah died. Meanwhile, the police station realizes there is a connection with Ha-nin.