A team of tenacious detectives study the minds of murderers at a time when Korea's first serial murders terrorized the nation. Based on true events.
E1 ∙ Red Cap Incident
Young-su is tired of an investigation with no progress, and creates a criminal behaviour analysis team by persuading detective Ha-yeong, who sees through the minds of others.
E2 ∙ Habits of Criminals
Ha-young faces dangerous criminals and struggles to see through them. He digs into the thoughts and intentions of those who commit evil crimes and follows in the footsteps of what made them fall into the abyss of evil.
E3 ∙ Ha Young Meets Tae Gu Again
A part of a victim's body is found in an alley, and a report of the disappearance of a five-year-old girl, Lee Soo-young, is received.
E4 ∙ What Must We Remember?
The Behavioural Analysis Team and Special Crime Squad join forces to search for the body of a missing girl.
E5 ∙ Looking into the Minds of Evil
Ha-young and Young-su have an interview with Jo Hyeon-gil. Soon, the two try to look inside his head, but are confused by the unbearable aura of evil.
E6 ∙ The Man With The Hiking Boots
Ha Young and Young Soo continue the search for the prime suspect in an elderly murder case. The team suspect a murder in Hwanghwa-dong is connected.
E7 ∙ A Scary Wolf Inside The Rabbit Burrow
A murderer who committed a crime against a wealthy elderly person disappears, and another murder case occurs that is similar but differs in method. Ha-young struggles to uncover the identity of the culprit.
E8 ∙ There Are No Perfect Crimes
After Young Chun is arrested he attempts to run away and lashes out at Tae Gu hurting her in the process.
E9 ∙ Becoming The Monster
Ha-young focuses on chasing after a brutal criminal, and the police struggle even more with the criminal whose tools and methods are gradually changing to vicious; Young-su looks back on his actions.
E10 ∙ When You Gaze Into the Abyss
Ha-young, who finally faces Nam Ki-tae, tries to figure out his inner heart and the full story of the incident; the police begin to thoroughly investigate Nam Ki-tae's house; Nam Ki-tae's vicious heart is revealed.
E11 ∙ The Victims And Their Families
A series of mysterious disappearances occur, and the police detect an unusual energy; Ha-young falls into a crisis, and Young-soo spends the day in pain because she thinks that what happened to Ha-young is because of her.
E12 ∙ The Hearts of Criminals
The team arrest the prime suspect in a missing women's case, but they don't have enough evidence to convict.
