Main •
Han Suk-kyu as Jang Tae-su : One of South Korea's top
profilers and a single father raising his only daughter, Ha-bin. He is a self-taught criminal behavior analyst who has earned unparalleled respect and trust within the police force since profiling was not even a word. However, when an incident shakes up his professional beliefs and his relationship with his beloved daughter, he struggles to uncover the truth in order to protect the one thing that means the world to him. •
Chae Won-bin as Jang Ha-bin : Tae-su's only daughter who is a high school student. She looks ordinary, but like her father, she has an extraordinary ability to keenly observe and understand people. She also hides a secret that will shake the life of her father.
Supporting ;Criminal Behavior Analysis Team •
Han Ye-ri as Lee Eo-jin : A member of Criminal Behavior Analysis Team under Tae-su at Yeonju Police Station. She studied in the United Kingdom and majored in
criminal psychology, and always prioritizes facts over emotions and cases over people. Although she respects Tae-su as a role model, she feels suspicious about his appearance as if he is hiding something. •
Roh Jae-won as Gu Dae-hong : A member of Criminal Behavior Analysis Team under Tae-su at Yeonju Police Station. He thinks that knowing criminals is a faster way to the truth than using traditional evidence. ;Violent Crimes Unit 1 of Criminal Investigation Division •
Yoon Kyung-ho as Oh Jeong-hwan : A passionate team leader of Violent Crimes Unit at Yeonju Police Station who thinks detectives are the core of the police force and is often in conflict with Tae-su. • as Kim Yong-su : A detective of Violent Crimes Unit at Yeonju Police Station who supports his team leader and takes care of his subordinates. He enjoys profiling and criminal psychology, takes personal interest to Tae-su but maintains a poker face because he is conscious of Jeong-hwan. • as Cho Kyung-bin : An action-oriented detective of Violent Crimes Unit at Yeonju Police Station who has to say what he wants to say to get relief. • as Park Jae-hoon : The youngest detective of Violent Crimes Unit at Yeonju Police Station. ;Forensic Science Investigation Team • Lee Yang-hee as Hwang Young-soo : Tae-su's ex-wife and Ha-bin's mother. She stands at the center of father-daughter narrative and amplifies the mystery surrounding it. ;People involve in the murder case • as Song Min-ah : A runaway girl who is presumed to be involved in some incident and becomes entangled with Ha-bin. • as Choi Young-min : A runaway family leader who cannot control his emotions and acts impulsively. •
Choi Yu-hwa as Kim Seong-hee : Ha-bin's homeroom teacher who is a person with conviction as a teacher and takes great care of his students. ;Others • Park Kyung-geun as Lee Seok-moon : One of the members of a runaway group. ==Production==