A daft but fun enough romp, in which Whoopi Goldberg is a nightclub singer who has to hide out from the Mob after witnessing a murder. Obviously the safest place to hide her is in a convent where Maggie Smith is the Mother Superior.
Obviously the convent has a terrible choir, so she can whip them into shape. With completely predictable results. But as I say, it's fun. Spawned not one but two sequels, I see.