Tae-soo, a legendary criminal profiler, goes home while working on a case to celebrate his daughter's birthday. However, he is called to a police substation to pick up his daughter who got herself in trouble. Later, Tae-soo realizes that Ha-bin could be involved in a murder case and starts doubting her.

To avoid repeating the nightmare of the past, Tae-soo wants to trust his daughter. However, every piece of evidence he comes across reveals traces of Ha-bin. What could Ha-bin be trying to keep secret? Meanwhile, during his investigation, Dae-hong discovers that Tae-soo is involved in this case.

Jung-hwan and Yong-soo visit Ha-bin at her place to interrogate her and see Tae-soo there. Tae-soo goes around trying to check Ha-bin's alibi on the 11th. He finds dashcam footage of Ha-bin that goes against her alibi. Ha-bin suggests to Tae-soo that they move, but Tae-soo insists on staying until he catches the real culprit. Meanwhile, cops find a stash of cash in Tae-soo's car and accuse him of accepting bribes.