This is the South Korean original version of this film. I admit that I was expecting a horror film and this it isn't. The main character has been imprisoned for 15 years in a room that looks to all intents and purposes like a hotel room. He is served food through a hatch but is never told who his captor is or why he has been imprisoned. His wife and daughter believe he is dead. the film tells the story of his release and his search to find his captor. It is brilliantly done but I found it took a long time in getting there. It has some memorable scenes (like the scene in a hallway with the hammer) but I found the film a bit overlong.