Tired of the crime overrunning the streets of Boston, Irish Catholic twin brothers Conner and Murphy are inspired by their faith to cleanse their hometown of evil with their own brand of zealous vigilante justice. As they hunt down and kill one notorious gangster after another, they become controversial folk heroes in the community. But Paul Smecker, an eccentric FBI agent, is fast closing in on their blood-soaked trail.

Based on the autobiography of Sonny Bono, this film focuses on the volatile relationship between Sonny and Cher during the early 60's to their messy divorce in the late 70's.

Skillfully framed by an unknown enemy for the murder of a priest, wanted vigilante MacManus brothers Murphy and Connor must come out of hiding on a sheep farm in Ireland to fight for justice in Boston.