Lee Hyun, a Criminologist working for the New York Police, returns to Korea to investigate a recent email that he received. He hopes to recover all of his early memories that he lost after the tragic murder of his father. On arrival at the airport, he deciphers some cryptographic symbology that leads him to a recent murder scene. Team 1 Investigative Unit arrives while he is there and mistakes him for the new Team Leader. However, Cha Ji-An, the Lead Investigator knows who he is because she has stalked him since her youth.

Plagued by insidious thoughts planted by serial killer Lee Joon-Yeong and recent events; Lee Hyun's father believes that he is becoming a monster. He isolates him in the basement to protect both him and the world. Joon-Yeong escapes from prison, murders his father and absconds with his brother. Lee Hyun discovers a painting at a murder scene that he believes may be his brother Lee Min’s.