Singer Deloris Carter, girlfriend to a prominent gangster, witnesses a gangland murder and flees the scene with criminals in pursuit. She seeks refuge at a local police station, and the New York Police Department arranges for her to hide in a convent with a group of nuns until the gangsters are apprehended and she can testify against them.

The clash between the strict convent lifestyle and Deloris’s flashy personality leads to many hilarious situations. As retribution for her rebellious behaviour, she is assigned to coach the convent choir. Unexpectedly, Deloris transforms the struggling choir into a sensational musical success, forming lasting and unlikely friendships along the way.