The drama is a psychological suspense drama, telling the story of a middle-aged investigator who is an outsider in the police, a young detective who was once a prosecutor and witnessed his father, a policeman, killing his mother. The three people involved in the tragic murder case that happened 15 years ago, three men and women whose lives collapsed because of this incident, in the special environment of personal apology, reveal the true face of the secret organization within the police and find the reason for their desperate survival. Kim Hyun-joo plays Han Tae-joo, a legendary secular lawyer. She was originally a prosecutor who was rising rapidly, but she resigned because she was seriously injured by robbers in her home, temporarily went abroad for recuperation, and after returning to China, she established a law firm that specializes in serving wealthy criminals. Deliberately defending criminals, causing trouble, causing the relevant people to become enemies and kill each other. Seo Kang-joon plays the role of Kim Young-jun, a suspicious policeman. He has excellent observation skills to see through the criminals, is brave, agile, and smart. Because of his "suspicion" that he doesn't believe in anything, he meets the supervisor and secular lawyer to form an illegal search team.