Saint Joan begins in 1429 at the castle of Vaucouleurs. Captain Robert de Baudricourt sits at a table and berates his steward for the fact that there are no eggs. The steward is convinced that the hens won’t lay eggs until De Baudricourt agrees to see “The Maid” who called on De Baudricourt two days ago and is still outside, speaking with soldiers and praying as she waits to be seen.
Reluctantly, De Baudricourt sends for her: she is Joan of Arc, a simple country girl of 17 or 18 years, dressed in men’s clothing and with a persuasive confidence about her. She informs De Baudricourt that he must give her a horse, armor, soldiers, and send her to the Dauphin: she is on a mission to raise the siege of Orleans, acting on the word of God as it is conveyed to her through the voices of saints she hears in her head. De Baudricourt balks at being ordered around by a young girl, but Joan won’t be refused. She tells him that two soldiers, Bertrand de Poulengey and Monsieur John of Metz, have promised to support and accompany her in her journey. Reluctantly, De Baudricourt yields to Joan’s demands. Joan and her soldiers depart for Chinon to meet with the Dauphin. After they leave, the steward rushes in to inform de Baudricourt that the hens have begun to lay eggs again, which de Baudricourt sees as proof that Joan really was sent by God.
Sometime later, Joan reaches the Dauphin at his castle in Chinon, in Touraine. She informs him that she has been sent by God to drive the English out of France and crown him king. The Dauphin is skeptical, having little interest in warfare and knowing that the English are more adept at fighting than the French, but things are so dire that France really has nothing to lose, and Joan eventually convinces him to let her command his army.
Joan and her army reach Orleans on April 29, 1429. On the river Loire, she meets Dunois, the Bastard of Orleans. Joan is impatient to begin fighting, which Dunois regards as overconfident and foolish. Dunois tells her the English are across the river, but he is hesitant to strike before the wind changes directions, as they must travel up the river and attack the English from the rear. Dunois has prayed incessantly for a west wind, but to no avail. Joan joins Dunois in praying. Shortly after this, Dunois’s page announces, with awe, that the wind has changed. Dunois sees this as evidence that Joan is sent from God, and they prepare to fight the English.
Sometime later, at a tent at an English camp, John de Stogumber (the Chaplain) and the Earl of Warwick discuss Joan: they believe she must be witch, as there is no other way to explain the French’s sudden rush of military victories.
Peter Cauchon (the Bishop of Beauvais) enters. Cauchon and Warwick discuss the problems Joan presents for their respective institutions. Cauchon believes Joan is guilty of heresy and, as a churchman, he believes he has an obligation to make sure she recants and saves her soul from damnation. At the same time, he acknowledges the danger Joan and her ideas pose for the Church: Joan’s relationship to God is unmediated by the Church—she believes she can talk to and understand God’s word without help from the Church—and this threatens the power the Church holds over its people.
Warwick is less concerned with the problem Joan poses to the Church but fears the threat Joan’s political ideologies pose to the existing feudal structure and society: acting on God’s orders, Joan wants the common people to be answerable to the king alone which would result in noblemen like Warwick being ripped of their power. Cauchon and Warwick don’t see eye to eye—Cauchon’s concerns are spiritual, and Warwick’s are temporal—but the two men can agree that they share Joan as a common threat to their respective institutions’ hold on power. They agree that Joan must be stopped.
Scene V takes place in the cathedral at Rheims. After numerous military victories, Joan has finally crowned Dauphin king: he is finally King Charles VII. Dunois enters the cathedral to find Joan praying. Having fulfilled her promises to God, Joan plans to return home to the country, but she suddenly asks Dunois if they can continue to fight and drive the English out of Paris before she leaves. Dunois has doubts that the French will be able to keep their victory streak going, and the Archbishop accuses Joan of obstinance, overconfidence, and the sin of pride. Charles VII, too, believes Joan is taking things too far. It’s also revealed that Joan’s actions and confidence have earned her many enemies. The crown, the military, and the Church all tell Joan that if her enemies capture her, she’s on her own: none of them will step in to rescue her from whatever gruesome fate is in store for her.
By May 30, 1431, Joan has been captured by the English and is on trial for heresy. Cauchon sincerely tries to give Joan a fair trial. He provides her with ample opportunities to recant and save her soul and body from destruction, but she refuses to reject the validity of her voices and place the authority of the Church before the direct word of God. Joan learns that she will be burned at the stake immediately because she refuses to recant. In a panic, she hurriedly signs a document rejecting her previous statements under the assumption that she will be allowed to go free.
When Cauchon informs her that she will be sentenced to life in prison, she rips the recantation to pieces and accepts her fate. She is immediately burned, except for her heart, which the Executioner reveals couldn’t be destroyed. The Chaplain rushes into the courtroom in a deranged panic: witnessing the cruelty and gruesomeness of Joan’s execution has had a profound effect on him, and he now regards his earlier enthusiasm to see her burned for witchcraft with shame and moral reprehension. He informs Warwick and Cauchon that a soldier offered Joan a makeshift cross in her final moments and regrets that he did nothing to prevent her burning.
Ladvenu, a Dominican monk who is sympathetic toward Joan, reveals that he, too, offered Joan a cross. When the flames grew so high that they threatened to enrobe Ladvenu as well as Joan, however, she told him to get down and save himself. Ladvenu believes the selflessness Joan demonstrated in her final hours is proof that she was sent from God, not from the devil, and that her death was not the end for her, but only the beginning of her redemption.
Twenty-five years after Joan’s death, Ladvenu comes to King Charles VII to announce that the charges brought against Joan have been reversed: the Church has cleared her name and smeared the reputations of her accusers. Charles VII is pleased to hear this, as it means he wasn’t crowned by a witch or heretic, and his title is therefore legitimate.
Joan then appears to Charles VII in a dream. He tells her the good news. One by one, those who condemned or abandoned Joan appear. Finally, a gentleman in 1920s clothing appears and informs the room that the Church has canonized Joan 500 years after her execution. Everybody praises her and apologizes for doubting her. When Joan asks whether she should come back to life and join them, however, they reject her, make excuses, and disappear. Joan cries out in despair: “O God that madest this beautiful earth, when will it be ready to receive thy saints? How long, O Lord, how long?”