The novel takes place in the middle of the 16th century. Madame de Chartres, who lived away from the court for many years after the death of her husband, and her daughter come to Paris. Mademoiselle de Chartres goes to a jeweler to select jewelry. There she was accidentally met by the Prince of Cleves, the second son of the Duke of Nevers, and fell in love with her at first sight. He really wants to know who this young lady is, and the sister of King Henry II, thanks to the friendship of one of her ladies-in-waiting with Madame de Chartres, introduces him the very next day to a young beauty who first appeared at court and aroused general admiration. Having found out that the nobility of his beloved is not inferior to her beauty, the Prince of Cleves dreams of marrying her, but fears that the proud Madame de Chartres will consider him unworthy of her daughter because he is not the eldest son of the duke. The Duke of Nevers does not want his son to marry Mademoiselle de Chartres, which hurts Madame de Chartres, who considers her daughter an enviable party. The family of another contender for the hand of the young lady - the Chevalier de Guise - also does not want to intermarry with her, and Madame de Chartres is trying to find a party for her daughter "that would raise her above those who considered themselves superior to her." She opts for the eldest son of the Duke de Montpensier, but because of the intrigues of the king's longtime mistress, the Duchess de Valantinois, her plans fail. The Duke of Nevers dies suddenly, and the Prince of Cleves soon asks for the hand of Mademoiselle de Chartres. Madame de Chartres, asking her daughter's opinion and hearing that she has no particular inclination towards the Prince of Cleves, but respects his dignity and would marry him less reluctantly than anyone else, accepts the prince's proposal, and soon Mademoiselle de Chartres becomes Princess of Cleves. Brought up in strict rules, she behaves impeccably, and virtue provides her with peace and universal respect. The Prince of Cleves adores his wife, but feels that she does not respond to his passionate love. This darkens his happiness.

Henry II sends the Count de Randan to England to Queen Elizabeth to congratulate her on her accession to the throne. Elizabeth of England, having heard about the glory of the Duke of Nemours, asks the count about him with such fervor that the king, after his report, advises the Duke of Nemours to ask the hand of the Queen of England. The Duke sends his confidant Linerol to England to find out the mood of the queen, and, encouraged by the information he received from Linierol, prepares to appear before Elizabeth. Arriving at the court of Henry II to attend the wedding of the Duke of Lorraine, the Duke of Nemours meets the Princess of Cleves at the ball and becomes imbued with love for her. She notices his feeling and, upon returning home, tells her mother about the duke with such enthusiasm that Madame de Chartres immediately realizes that her daughter is in love, although she herself does not realize it. Protecting her daughter, Madame de Chartres tells her that the Duke of Nemours is rumored to be in love with the Dauphin's wife, Mary Stuart, and advises her to visit the Dauphine queen less often so as not to be involved in love affairs. The Princess of Cleves is ashamed of her penchant for the Duke of Nemours: she should have feelings for a worthy spouse, and not for a person who wants to use her to hide her relationship with the Queen Dauphine. Madame de Chartres is seriously ill. Having lost the hope of recovery, she gives her daughter orders: to retire from the court and sacredly remain faithful to her husband. She assures that leading a virtuous life is not as difficult as it seems - it is much more difficult to endure the misfortunes that a love adventure entails. Madame de Chartres dies. The Princess of Cleves mourns her and decides to avoid the company of the Duke of Nemours. The husband takes her to the village. The Duke comes to visit the Prince of Cleves in the hope of seeing the princess, but she does not accept him.

The Princess of Cleves returns to Paris. It seems to her that her feelings for the Duke of Nemours have faded away. The Queen Dauphine informs her that the Duke of Nemours has abandoned his plans to ask the hand of the Queen of England. Everyone believes that only love for another woman could move him to this. When the princess of Cleves suggests that the duke is in love with the dauphine queen, she replies: the duke never showed any feelings for her, except for secular deference. Apparently, the chosen one of the duke does not reciprocate, because his closest friend of the species de Chartres - the uncle of the Princess of Cleves - does not notice any signs of a secret connection. The Princess of Cleves guesses that his behavior is dictated by his love for her, and her heart is filled with gratitude and tenderness for the duke, who, out of love for her, neglected the hopes for the English crown. The words, as if accidentally dropped by the duke in conversation, confirm her guess.

In order not to betray her feelings, the princess of Cleves diligently avoids the duke. Mourning gives her a reason to lead a secluded life, her sadness also does not surprise anyone: everyone knows how much she was attached to Madame de Chartres.

The Duke of Nemours steals a miniature portrait of the Princess of Cleves. The princess sees this and does not know what to do: if you demand to publicly return the portrait, then everyone will know about his passion, and if you do it face to face, then he can declare his love to her. The princess decides to remain silent and pretend that she has not noticed anything.

In the hands of the Queen Dauphine falls a letter, allegedly lost by the Duke of Nemours. She gives it to the Princess of Cleves so that she reads it and tries to determine by handwriting who wrote it. In the letter, an unknown lady reproaches her lover for infidelity. Princess of Cleves is tormented by jealousy. But there was a mistake: in fact, the letter was not lost by the Duke of Nemours, but by the species de Chartres. Fearing to lose the favor of the reigning queen Maria de Medici, who demands from him complete self-denial, de Chartres asks the Duke of Nemours to recognize himself as the addressee of the love letter. In order not to incur the reproaches of his beloved on the Duke of Nemours, he gives him an accompanying note, from which it is clear who wrote the message and to whom it is intended. The Duke of Nemours agrees to help out Vidam de Chartres, but goes to the Prince of Cleves to consult with him on how best to do this. When the king urgently summons the prince to him, the duke is left alone with the princess of Cleves and shows her a note testifying to his innocence in the lost love letter.

The Princess of Cleves leaves for the Colomier castle. The duke, unable to find a place for himself from melancholy, goes to his sister the Duchess de Mercer, whose estate is located next to Colomier. While walking, he wanders into Kolomye and accidentally overhears the conversation between the princess and her husband. The princess confesses to the prince that she is in love and asks permission to live away from the world. She hasn't done anything wrong, but she doesn't want to be tempted. The prince remembers the loss of the princess's portrait and suggests that she gave it to him. She explains that she did not give it at all, but she witnessed the theft and kept silent so as not to provoke a declaration of love. She does not mention the name of the person who awakened such a strong feeling in her, but the duke realizes that it is about him. He feels immensely happy and at the same time immensely unhappy.

The Prince of Cleves is eager to find out who owns the thoughts of his wife. By cunning, he manages to find out that she loves the Duke of Nemours.

Amazed by the princess's deed, the Duke of Nemours tells Vidam de Chartres about him, without naming them. Vidam guesses that the Duke is involved in this story. He himself, in turn, tells his mistress Madame de Martigues "about the extraordinary act of a certain person who confessed to her husband the passion she felt for another" and assures her that the subject of this ardent passion is the Duke of Nemours. Madame de Martigues retells this story to the Queen Dauphine, and she tells the Princess of Cleves, who begins to suspect her husband of having entrusted her secret to one of her friends. She accuses the prince of divulging her secret, and now she is known to everyone, including the duke. The prince swears that he kept a sacred secret, and the couple cannot understand how their conversation became known.

Two weddings are celebrated at the court at once: the daughter of the king, Princess Elizabeth, with the king of Spain and the sister of the king, Margaret of France, with the Duke of Savoy. The King is organizing a tournament for the occasion. In the evening, when the tournament is almost over and everyone is going to disperse, Henry II challenges the Count of Montgomery to a duel. During the duel, a shard of the spear of the Earl of Montgomery hits the king in the eye. The wound is so serious that the king soon dies. The coronation of Francis II is to take place in Reims, and the entire court is sent there. Learning that the Princess of Cleves will not follow the court, the Duke of Nemours goes to her to see her before leaving. At the door, he encounters the Duchess of Nevers and Madame de Martigues, leaving the princess. He asks the princess to accept him, but she communicates through the maid that she felt bad and cannot accept him. The Prince of Cleves learns that the Duke of Nemours visited his wife. He asks her to list everyone who visited her that day, and, not hearing the name of the Duke of Nemours, asks her a direct question. The princess explains that she has not seen the duke. The prince suffers from jealousy and says that she made him the most unfortunate person in the world. The next day he leaves without seeing his wife, but still sends her a letter full of sorrow, tenderness and nobility. She responds to him with assurances that her behavior was and will be impeccable.

Princess of Cleves leaves for Kolomye. The Duke of Nemours, under some pretext asking the king for leave to travel to Paris, leaves for Colomier. The Prince of Cleves realizes the Duke's plans and sends a young nobleman from his retinue to watch him. Having made his way into the garden and going to the window of the pavilion, the duke sees how the princess is tying bows on a cane that used to belong to him. Then she admires the painting, where he is depicted among other soldiers who took part in the siege of Metz. The Duke takes a few steps, but hits the window frame. The princess turns around at the noise and, noticing it, immediately disappears. The next night, the Duke comes again under the pavilion window, but she does not appear. He visits his sister Madame de Mercer, who lives next door, and deftly leads the conversation to the fact that his sister herself invites him to accompany her to the Princess of Cleves. The princess makes every effort not to be left alone with the duke for a minute.

The Duke returns to Chambord, where the king and court are. The prince's envoy arrives in Chambord even before him and reports to the prince that the duke spent two nights in a row in the garden, and then was in Colomier with Madame de Mercer. The prince is unable to endure the misfortune that has befallen him, he begins to develop a fever. Upon learning of this, the princess hurries to her husband. He meets her with reproaches, because he thinks that she spent two nights with the duke. The princess swears to him that she did not even think to cheat on him. The prince is glad that his wife is worthy of the respect that he had for her, but he cannot recover from the blow and dies after a few days. Realizing that she is the culprit in her husband's death, the Princess of Cleves feels a burning hatred for herself and the Duke of Nemours. She bitterly mourns her husband and for the rest of her life intends to act only as it would be pleasing to him if he were alive. Mindful of the fact that he expressed fear that after his death she would not marry the Duke of Nemours, she firmly decides never to do this.

The Duke of Nemours reveals to Vidam de Chartres his feelings for his niece and asks to help him see her. Vidam readily agrees, for the duke seems to him the most worthy contender for the hand of the Princess of Cleves. The Duke declares his love for the princess and tells how he learned about her feelings for him, having witnessed her conversation with the prince. The Princess of Cleves does not hide that she loves the Duke, but she firmly refuses to marry him. She considers the duke to be guilty of the death of her husband and is firmly convinced that marriage with him is contrary to her duty.

Princess of Cleves leaves for her distant possessions, where she is gravely ill. Having recovered from her illness, she moves to the holy monastery, and neither the queen nor the species succeeds in persuading her to return to the court. The Duke of Nemours goes to her himself, but the princess refuses to accept him. Part of the year she lives in the monastery, the rest of the time - in her domain, where she indulges in pursuits even more pious than in the strictest monasteries. "And her short life will remain an example of inimitable virtue."