Jang Tae Su is a legendary criminal profiler in Korea. He was one of the pioneers in his field and paved the way for criminal behaviour analysts in the country. He has earned absolute respect and trust within the police force. At home, he is a single parent raising his daughter on his own. Jang Tae Su is working on a murder case and realises that his daughter is involved in it. The discovery shatters all his professional convictions and strains his relationship with his daughter. To protect his daughter, Jang Tae Su fights to uncover the truth.