Songbird Deloris Van Cartier (Whoopi Goldberg) needs protection after inadvertently seeing her gangster boyfriend, Vince (Harvey Keitel), commit murder. She's rechristened Sister Mary Clarence and stashed in a convent, where her heretical behavior shakes up the order -- especially starchy Mother Superior (Maggie Smith). Relegated to the choir, Deloris peppers their repertoire with doo-wop and soon draws the media's attention ... and Vince's.