Lin Shen, a deliveryman with a troubling appearance, was once the youngest specially appointed criminal psychologist of the Ministry of Public Security. He was kicked out of the police force due to an unjust case. Ten years later, when he was delivering food late at night, the elevator door opened and a woman in a red trench coat stood inside - exactly the same as when she disappeared ten years ago.
He and Su Wan, the cold-faced female detective captain who was suspended, were forced to join forces to track down a serial disappearance case that spanned ten years. With every step they take, the darkness gets closer - they discover that the murderer is hiding inside the police station, and he is the first group of criminal police officers to investigate the disappearance case that year.
When the truth finally emerged, Lin Shen discovered a fact that was horrifying to think about: the first order he placed was ordered by the murderer.
