So Ji-sub already knew who had kidnapped him in the past.
Joo Joong-won was kidnapped with his girlfriend for a ransom of 10 billion won. He lived but his girlfriend Cha Hee-joo, didn't.
Those who remembered what had happened rumored that her ghost was around him. This was because something happened to every woman who came around him after that. Tae Gong-sil (Kong Hyo-jin) also saw her ghost.
Tae Gong-sil watched a TV program that revised that day's incident again. The criminal wasn't caught and the statute of limitations was running out. She figured he was cold and bad tempered in guilt of his dead girlfriend.
However, Joo Joong-won surprised her by telling her, "If you can see ghosts, tell her. Bitch".
Actually, he knew who the criminal was. It was his girlfriend. He thought about the past and said, "I am mad that you died like that Cha Hee-joo".
The dyslexic trauma he had been suffering turned out to be because of his girlfriend's betrayal.