Whoopi Goldberg stars in Emile Ardolino's comedy thriller as Deloris Van Cartier, a lounge singer at a casino managed by her lover Vince LaRocca (Harvey Keitel).
He's also a drugs baron and when she accidentally interrupts him in the process of rubbing out a stool pigeon, she has to run for her life. To keep her safe until LaRocca can be charged, the police arrange for her to become Sister Mary Clarence at a nunnery overseen by stern Mother Superior (Maggie Smith).
But you can't keep a good singer down and Sister Mary has soon so successfully invigorated the choir with her musical talent that the church is packed - and there is even a call from Rome for a Papal performance.
Unfortunately, thanks to an inside man in the police department, LaRocca learns of her whereabouts and sets out to prevent her testifying; can her new found friends, the nuns, protect her?