In Korea, you are not allowed to work on a secret investigation or be a private eye. This is why Jiwoo's official job title is "P.I.A (Private Investigation Administrator)". Many years ago, Jiwoo handled the case of Asian couple who died at a casino in Las Vegas. As a result, Jiwoo received astronomical amount of money as the reward and also became one of the top detectives. Jiwoo didn't know this incident would rebound upon him at that time. He loses his best friend Gyudong and meets a lady named Jini. Jini requests Jiwoo to find a person calls Melchidec. Jini believes that Melchidec is the one who killed her foster parents and she will also get killed by him. She thinks Jiwoo drew the conclusion that her adoptive parents committed suicide, even though he knows all these facts. As Jiwoo and Jini come closer to getting the full story of the case, they notice that they fall in love for each other.