Please answer the following question: I am a movie director and I just received the following movie plot. Could you help me answer this question? If not, let me know by writing "Not answerable". Plot title: Oldboy Movie plot: In 1988, a businessman named Oh Dae-su (Choi Min-sik) is arrested for drunkenness, missing his daughter's 4th birthday. After his friend Joo-hwan (Ji Dae-han) retrieves him from the police station, they go to a phone booth for Dae-su to call home. While Joo-hwan is talking to Dae-su's wife, Dae-su is kidnapped, and wakes up in a sealed hotel room where food is delivered through a trap-door. By watching the television, Dae-su learns that his wife has been murdered and that he is the prime suspect. Dae-su passes the time shadow-boxing, planning revenge, and attempting to dig a tunnel to escape. In 2003, 15 years after he was imprisoned, and just before digging himself to freedom, Dae-su is hypnotized and wakes up on a roof-top with a suit. After interacting with a jumper on the rooftop, Dae-Su tests his fighting skills on a groups of young toughs and is mysteriously handed a cell phone and money by a beggar. He receives a taunting phone call from his captor, who refuses to explain the reason for his imprisonment. Later he collapses at a Sushi restaurant and is taken in by Mi-do (Kang Hye-jung), the restaurant's young chef. After he recovers, Dae-su tries to find his daughter and the location of his prison. He discovers that his daughter was adopted by a Swedish couple, and gives up trying to contact her. Dae-su locates the Chinese restaurant which made food for his prison, and finds the prison by following a delivery man. Apparently it is a private prison where people can pay to have others incarcerated. Dae-su enters the prison and tortures the warden, Mr Park, who doesn't know the identity of Dae-su's captor but reveals that Dae-su was imprisoned for "talking too much." While leaving the prison, Dae-su is attacked by a large number of guards but manages to defeat all of them. Dae-su's captor, a wealthy man named Lee Woo-jin (Yoo Ji-tae), contacts Dae-su again and gives him the following ultimatum: if Dae-su discovers the motive for his imprisonment within 5 days, then Woo-jin will kill himself. Otherwise,... My question: How did Oh Dae-su find out his wife was murdered?
A:
television