The Boondock Saints is a 1999 action thriller film written and directed by Troy Duffy. It follows the story of twin brothers, Conner and Murphy MacManus, who live in South Boston. One night, they are attacked by Russian mobsters in a local bar. They defend themselves and kill the mobsters in self-defense. They believe that they have been chosen by God to rid Boston of criminals and they begin to execute criminals who they believe have evaded justice.
As the brothers continue their mission, they gain a cult-like following and become known as "the Saints" among the people of Boston. An FBI agent, Paul Smecker, is assigned to investigate the killings and he becomes fascinated by the brothers' methods. Smecker sympathizes with the brothers' cause and begins to work with them, giving them advice on how to outwit the police.
The brothers' actions attract the attention of the Russian and Italian Mafia, who see them as a threat to their power. The Mafia sends hitmen after the brothers, leading to a violent shootout that leaves several people dead. Smecker helps the brothers escape, and they continue their mission.
In the end, the brothers face off against the Mafia boss who has been behind much of the city's crime. With the help of Smecker, the brothers are able to take him down and bring justice to the people of Boston.
The movie received mixed reviews upon its release but has since gained a cult following and has been hailed for its unique storyline and intense action scenes. Sequel movies were released in 2009 and 2019.