Place: Paris and Compiègne, 1789-94Time: during the French Revolution
The pathologically timid Blanche de la Force decides to retreat from the world and enter a Carmelite monastery. The Mother Superior informs her that the Carmelite Order is not a refuge; it is the duty of the nuns to guard the Order, not the other way around. In the convent, the jolly Sister Constance tells Blanche (to her consternation) that she has had a dream that the two of them will die young together. The prioress, who is dying, commits Blanche to the care of Mother Marie. The Mother Superior passes away in great agony, shouting in her delirium that despite her long years of service to God, He has abandoned her. Blanche and Mother Marie, who witness her death, are shaken.
Sister Constance remarks to Blanche that the prioress' death seemed unworthy of her, and speculates that she had been given the wrong death, as one might be given the wrong coat in a cloakroom. Perhaps someone else will find death surprisingly easy. Perhaps we die not for ourselves alone, but for each other.
Blanche's brother, the Chevalier de la Force, arrives to announce that their father thinks Blanche should withdraw from the monastery, since she is not safe there (being both an aristocrat and the member of a religious community). Blanche refuses, saying that she has found happiness in the Carmelite Order, but later admits to Mother Marie that it is fear (or the fear of fear itself, as the Chevalier expresses it) that keeps her from leaving.
The chaplain announces that he has been forbidden to preach (presumably for being a non-juror under the Civil Constitution of the Clergy). The nuns remark on how fear now rules the country, and no one has the courage to stand up for the priests. Sister Constance asks, "Are there no men left to come to the aid of the country?" "When priests are lacking, martyrs are superabundant," replies the new Mother Superior. Mother Marie says that the Carmelites can save France by giving their lives, but the Mother Superior corrects her: it is not permitted to become a martyr voluntarily, martyrdom is a gift from God.
A police officer arrives and announces to the community that the Legislative Assembly has nationalized the monastery and its property, and the nuns must give up their religious habits. When Mother Marie acquiesces, the officer taunts her for being eager to dress like everyone else. She replies that the nuns will continue to serve, no matter how they are dressed. "The people has no need of servants," proclaims the officer haughtily. "No, but it has a great need for martyrs," responds Mother Marie. "In times like these, death is nothing," he says. "Life is nothing," she answers, "when it is so debased."
In the absence of a new prioress, Mother Marie proposes that the nuns take a vow of martyrdom. However, all must agree, or Mother Marie will not insist. A secret vote is held; there is one dissenting voice. Sister Constance declares that she was the dissenter, and that she has changed her mind, so the vow can proceed. Blanche runs away from the monastery, and Mother Marie goes to look for her, finding her in her father's library. Her father has been guillotined, and Blanche has been forced to serve her former servants.
The nuns are all arrested and condemned to death, but Mother Marie is away (with Blanche, presumably) at the time. The chaplain tells Mother Marie that since God has chosen to spare her, she cannot now voluntarily become a martyr by joining the others in prison. The nuns (one by one) slowly mount the scaffold, singing the Veni Creator Spiritus. At the last minute, Blanche appears, to Constance's joy. Having seen all the other nuns executed, as she mounts the scaffold Blanche concludes their hymn with Deo patri sit gloria (Glory be to God the Father).