Matt Scudder (Liam Neeson) is a former policeman of New York Police Station and now working as an illegal private detective after recovering from alcoholism. He is paid by Kenny Kristo (Dan Stevens), a drug kingpin to investigate who kidnapped and kill his wife. Following clues and associating them together, Matt Scudder realizes that this case is related to a series of cases he was responsible for when he was a policeman.