Ji Oh is a taciturn man who is thrust into the world without a single clue of who he is and who has a different "strength" and "secret" compared to ordinary people. After endless confliects with those who are searching for themselves, Ji Oh must work to find answers to the numerous questions surrounding his own existence.Goo Reum is transferred from the Major Crimes Investigative Unit while investigating the corruption of a superior officer. Goo Reum is a person who acts before she thinks and bulldozes on ahead once she makes up her mind. She ends up with her life turned upside down when she meets with Ji Oh while on the case of a missing child. Her parents disappeared when she was only a young child. Goo Reum chases after the truth behind her parents' disappearance.