When someone is a witness in any kind of a heavy crime, that person gets to testify and before the time for that comes, it is placed in the Witness Protection Program, for a new identity and history until the trial, so the police can avoid that person being killed by the criminals. That happens to one of the world famous singers, Deloris Van Carter (Whoopi Goldberg). After she is a witness in a murder committed by her boyfriend, Deloris goes to police and gets placed in the last place he would look for her- in a monastery. From the beginning, the Mother Superior (Maggie Smith) is more than reluctant to this idea, but the police officers manage to convince her into cooperating and taking Delores in. Soon, Deloris makes friends with Sister Mary Robert (Wendy Makkena), Sister Mary Lazuras (Mary Wickes) and Sister Mary Patrick (Kathy Najimy). After the Mother Superior catches three of them sneaking out at night and going out in the nightclub, she punishes them by putting them in the choir. That is where the whole comedy starts and their adventures as well, because the choir is far from even being considered good. But, now, when Deloris is the main star of this choir, things are about to change.