A Reno lounge singer named Deloris Van Carter witnesses her mobster boyfriend killing an employer. She is then hidden in a convent under a witness protection program. She soon makes friends with the nuns especially Sister Mary Robert, Sister Mary Lazuras and Sister Mary Patrick. After the Mother Superior catches Deloris going out to a bar in the night time followed by Mary Robert and Mary Patrick she orders her to join the church choir. Only to find her coaching the choir and turning them into swingin' singin' sisters. The choir proves to be a big success with the surrounding neighborhood, but will Deloris' boyfriend track her down?
