Events unfold in Pisa at the end of the XV century. Head of the Pisa garrison Guido Colonna discusses the situation with his lieutenants Borso and Torello: Pisa is surrounded by enemies – the troops of the Florentines, and the troops sent by Venice to help the Pisans could not get through to them. The city is about to start a famine. The soldiers did not have gunpowder or bullets. Guido sent his father Marco to negotiate with Princiwallet, the mercenary commander of the Florentine army. There are various rumors about Princhivala: it is portrayed as cruel and treacherous, sometimes dangerous, but honest and noble. Returns Marco. He says that Princivalle received him as an honorable guest. Marco enthusiastically tells how he argued with Princivalle on Plato’s dialogues, how he met the Florentine commander of the famous scientist Ficino in the camp tent,
Guido interrupts his father’s story, trying to find out how his negotiations
with Princivalle ended. Marco tries to warn Guido of rash decisions and then reports that Princiwalley, after learning about the fate he has prepared (he is going to be accused of treason in Florence and executed), offers the city of Pisa military assistance or promises to send three hundred carts with ammunition and food. But Princiwallet makes a condition (Marco hardly makes himself pronounce it), so that as a sign of victory, he came to him alone, “came completely naked, so that she could only be covered with a cloak” – Guido’s wife, Giovanna. Guido is outraged. He is ready to die himself and ruin the city, but it turns out that Giovanna already knows from Marco about the condition of the rescue of Pisa and is ready to sacrifice himself Guido is trying to prevent his wife. Realizing that this is useless,
In his camp near Pisa, in the tent where the weapons and furs are lying disorder, there are chests with jewels and shiny fabrics, Princiwalle awaits a decision of his fate: if his offer is rejected, Marco should return, if it is accepted, it will light up on the bell tower in the city
the fire that proclaims the coming of Giovanna, Monna of Bath, the woman Princivalla loves since childhood. The signal light comes on. Princivalla rejoices. But before the appearance of Monna Bath Princivalla will meet with Trivulzio, the commissioner of the Florentine Republic. Trivulzio assures Princivalle of his sincere affection and warns of the machinations of ill-wishers. He calls on the commander immediately to seize Pisa in order to return to his side those who are hostile to him, returning to Triumph in Florence. Princivalla exposes the duplicity of Trivulzio, showing him his own denunciations, as a result of which Princiwalle was to perish, because the people of Florence idolized him and could follow him if Princiwallet suddenly came to mind to rebel against his superiors. Sensing that he was exposed, Trivulzio throws with a dagger on Principulva, who manages to deflect the blow, and the dagger only touches his face. Princivalle does not understand how one can ruin a person on suspicion alone, out of fear of imaginary danger. At the same time, he respects the devotion of Trivulzio to his native Florence, Princiwallet orders the removal of Trivulzio, but warns that no one touches him with a finger. Vedio, the adjutant of Princiwalle, binds his wound. A shot can be heard in the distance. Principia is concerned: suddenly it was shot at Monna Vanna? Vedio leaves to learn and, after returning, calls Princivalle. Then he disappears, and in the tent appears Monna Bath. She is really easily injured in the shoulder, but refuses to bandage the wound. Principia shows Vanna how the carts for provisions for her coming to Pisa with provisions and ammunition are sent to her.
Having seated Vanna on her bed, Princivalle tells her about her love. The bath is struck by the power of feeling. She does not immediately recognize in the commander of the enemy army blond boy Janello, whom she played in her childhood. Father took Janello to Africa. After long walks in the desert, after the Turkish and Spanish captivity, he returns to his hometown and learns that Giovanna married the most powerful and rich man in Pisa. He had nothing to offer her. Janello becomes a mercenary commander, participates in various wars, his name becomes glorious, and here the case leads him under the walls of Pisa… Giovanna reproaches him for indecision. “Do not flatter yourself, I do not like you,” she says to Princivalle, “and at the same time the soul of love in me rushes, murmurs, resents when I think that to a man who loved me so fervently,
The bath is embarrassed that for her sake Princivalle has foolishly charted his future, his fame, life itself, and he explains to her that he did not sacrifice anything for her: he is a mercenary and is faithful only until they are true to him (” , I would not change her for the sake of the most ardent love, “he notes). Vedio warns Princivalle of the appearance in the camp of the Florentines, ready to arrest him. Giovanna, in order to save Princivalle, invites him to go with her to Pisa. Over the city to which the Bath and Principia are heading, there is a glow of festive lights. Bath is happy and thankful to Princiwal. She kisses him on the forehead.
In Pisa, in his palace Guido suffers from shame, from humiliation. He does not want to see his father, who pushed Giovanna to the victim. And he is going to forgive her, but only when her rapist is killed. “It’s probably impossible to forget her misdemeanor, but he can go so far into the past that his jealousy will not find…” Marco is ready to leave the city, he only wants to see how Giovanna will meet with Guido. Hear the cheering crowds: “Our Monna Bath!”, “Glory to Monna Vanne!” Marco, accompanied by Borso and Torello, enters the terrace, Guido remains alone. Marco’s eyes are incapable of discerning where Giovanna is, and Borso tells him about her triumphant approach. Next to her is an unknown person, whose face is hidden by a bandage. Marco hugs Giovanna. Appears Guido. Bath wants to talk to him, rush to him in the arms, But he stops and pushes Giovanna with a sharp movement. He drives the crowd from the walls of his palace, then tries to tear the bandage from Princivalle’s face to find out who it is. The bath rises between them. She reveals Guido that she is her savior and calls his name Princivalle. Guido also decides that Giovanna brought Princivalle to Pisa to take revenge on him. Running out onto the terrace, Guido loudly screams that the enemy is caught. Now he wants the crowd to gather. Guido longs to hear Bath’s story about how she managed to lure Princivalle. Bath urges her husband to believe her and tells that Princivalla did not touch her. But Guido’s common sense does not allow him to believe his wife. He turns to the crowd with the question, does anyone believe Giovanna? Only Marco believes her. And Guido puts Giovanna in front of the choice: either she confesses that Princivalle had her, or, if she insists that he did not touch her, he will be executed. Then the Bath to save Princivalle, lies that he possessed her, that she lured him into the city with kisses (while she passionately kisses Princivalla, whispers to him words of love and conjures silence). She demands that she be given the key to Princivalle’s dungeon, and Guido promises that the guard will now bring her the key.
Marco understands and accepts the high deception of Monna Bath. Guido is happy, for him the past is a heavy dream. “Oh yeah, you’re right,” he answers, “it was a heavy dream… But now – the light will start…”