An ordinary Bangkok bachelor, Ray's life is turned upside down when he is convicted and jailed for the accidental killing of a pedestrian. Life behind bars is bitter and violent - but then the warden offers him respite from his torment... by asking him to monitor and report on the activities of his fellow inmates. He does the job well but he soon begins to realize that many of those incarcerated are innocent or victims of bad circumstances - but what can he do to help and how much danger is he placing himself in?