The novel is set in the middle of the 16th century. Madame de Chartres, for many years after the death of her husband, has lived far away from the court, and now came with her daughter to Paris. Mademoiselle de Chartres goes to a jeweler to choose something. There she accidentally meets the Prince of Cleves, the second son of the Duke of Nevers, who falls in love with her at first sight. He wants to know who this young lady is, and the sister of King Henry II, because of the friendship of one of her maids of honor with Madame de Chartres, introduces young beauty at the court the next day, and she causes a general admiration. Seeing that the nobility of the beloved is not inferior to her beauty, Prince of Cleves wants to marry her, but is afraid that the proud Madame de Chartres deems him unworthy of her daughter because he was 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, thinking her daughter to be an enviable party. The family of another pretender of the hand of a young lady - the Chevalier de Guise - does not want to intermarry, and Madame de Chartres is trying to find her daughter a party, which would have ennobled her over those who considered themselves above her. Her choice falls on the eldest son of the Duke de Montpensier, but because of the intrigues of a longtime mistress of the King Duchesse de Valantinua, her plans suffer crash. The Duke of Nevers suddenly dies, and the Prince of Cleves soon asks for the hand of Mademoiselle de Chartres.
Madame de Chartres asked her daughter’s opinion and heard that she had no special inclination towards the Prince of Cleves, but respected his dignaty so she accepted the proposal; soon, Mademoiselle de Chartres became the princess of Cleves. Being raised in strict rules, she behaves impeccably, and virtue gives her peace and respect. The Prince of Cleves loves his wife, but feels that she does not respond to his passionate love. It clouds his happiness.
Henry II sent Count de Randall to England to the Queen Elizabeth to congratulate her on assuming the throne. Elizabeth of England, having heard of the fame 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 approximate Lineroly to England to find out the mood of the queen, and, encouraged by the information received from Lineroly, prepares to appear before Elizabeth. Arriving at the court of Henry II to attend the wedding of the Duke of Lorraine, Duke of Nemours at the ball gets acquainted with the princess of Cleves and got imbued with love for her. She notices his senses and when returns home tells her mother about the Duke with such enthusiasm, that Madame de Chartres immediately realizes that her daughter is in love, although she does not realize it herself. 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 not to visit the Queen-Dauphin too often not to be involved in love affairs.
The Princess of Cleves is ashamed of her addiction to the Duke of Nemours: she is better to be a worthy wife, and not have feelings to the person who wants to use her to hide his relationship with the Queen-Dauphin. Madame de Chartres gets seriously ill. Having lost hope of recovery, she gives her daughter advuce: to retire from the court and stay religiously faithful to her husband. She says that to lead a virtuous life is not as difficult as it seems - is much more difficult to transfer misfortunes, which a love affair would entail. 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 away to the village. The Duke comes to visit the Prince of Cleves hoping to see the princess, but she does not accept him.
The Princess of Cleves returns to Paris. She thinks that her feelings to the Duke of Nemours extinguished. The Queen-Dauphin informs her that the Duke of Nemours abandoned his plans to ask the hand of the English Queen. Everyone thinks that just love for another woman might encourage him to do so. When the Princess of Cleves suggests that the Duke is in love with the queen-dauphin, she answers that the Duke never showed her any feelings other than secular piety. Apparently, the darling of the Duke does not respond to his feelings, for his closest friend de Chartres - Princess of Cleves’ uncle - did not notice any signs of secret communication. The Princess of Cleves guesses that his behavior is dictated by his love for her, and her heart is filled with gratitude and affection for the Duke. Words, as if by accident said by the Duke in a conversation, confirmed her surmise.
In order not to betray his feelings, the Princess of Cleves studiously avoids the Duke. Mourning gives her the right to lead a secluded life; her sadness also is no surprise to anyone, as they all know how much she was tied to Madame de Chartres.
The Duke of Nemours steals a miniature portrait of the Princess of Cleves. Princess sees this and does not know what to do, if the requests to return the portrait publicly, then everyone will know about his passion, and if to do it with an eye for an eye, he can declare his love to her. Princess decides to remain silent, and to pretend that she did not notice anything.
The Queen-Dauphin gets a letter, supposedly lost by the Duke of Nemours. She gives it to the Princess of Cleves, that she reads it and tries to identify the handwriting. In a letter an unknown woman accuses her lover of infidelity. The Princess of Cleves is tormented by jealousy. But there was a mistake: in fact not the Duke of Nemours lost letter, but de Chartres. Being afraid to lose the disposition of the reigning Queen Marie de Medici, who demands of him a complete self-denial, de Chartres asks the Duke of Nemours to pretend to be the addressee of a love letter. The Duke of Nemours agrees to help, but goes to the Prince of Cleves, to consult with him, how to do it. When the king urgently summons the Prince, the Duke remains alone with the Princess of Cleves, and shows her a note indicating his innocence to the lost love letters.
Princess of Cleves goes to Colomiers Castle. The Duke goes to his sister the Duchess de Merkёr whose property is located adjacent to Colomiers. During the walk he wanders in Colomiers and accidentally overhears a conversation of the princess with her husband. The princess confesses that she is in love, and asks permission to live away from the world. She has done nothing reprehensible, but does not want to be tempted. The prince remembers the missing of her portrait and suggests that she has given it herself. She explains that she did not give it, but witnessed the theft and did not say anything, so as not to cause a declaration of love. She does not mention the person's name, whi has awakened in her such a strong feeling, but the Duke understands that they are talking about him. He feels immensely happy and unhappy at the same time. The Prince of Cleves is eager to find out who owns the thoughts of his wife. He manages to find out that she loves the Duke of Nemours.
Amazed by the princess’s deed, the Duke of Nemours tells about it de Chartres, without naming names. The last realizes that the Duke has to do with this story. He himself, in turn, tells about it to his mistress Madame de Martigues – of "the extraordinary deed of some person, who confessed her husband of the passion she felt for the other," and says that the object of that ardent passion is the Duke of Nemours. Madame de Martigues retells the story to the Queen-Dauphin, and she to the Princess of Cleves, who begins to suspect her husband that he trusted her secret to someone of his friends. She accuses the prince that he divulged her secret, and now it is known to everyone, including the Duke. The prince swears that faithfully kept the secret, and spouses do not understand how their conversation became known.
Two weddings are being celebrated at the court at once: the king's daughter Princess Elizabeth with the Spanish king, and the king's sister Marguerite of France with the Duke of Savoy. The king organizes on this occasion the tournament. In the evening, when the tournament is almost over and everyone is going to diverge, Henry II calls for the fight the Count of Montgomery. During the match a fragment of the lance of Count Montgomery gets into the king's eye. The wound is so serious that the king soon dies. The coronation of Francis II is to be held in Reims, and the whole court goes there. Upon learning that the Princess of Cleves does not follow the court, the Duke of Nemours goes to her to see her before leaving. At the door he confronts with the Duchess of Nevers and Madame de Martigues, coming out of the princess’s house. He asks the princess to accept him, but she passes through the maid she feels unwell and can not accept him. Prince of Cleves becomes aware that the Duke of Nemours came to his wife. He asks her to list all those who visited her that day, and when did not hear the name of the Duke of Nemours, he asks a direct question. Princess explains that she had not seen the Duke. Prince suffers from jealousy and says that she has made him the most miserable man on earth. The next day he leaves without seeing his wife, but still sends her a letter, full of sorrow, tenderness and generosity. She answers him with assurances that her behavior is, was and will be perfect.
Princess of Cleves goes to Colomiers. The Duke of Nemours, under some pretext, asks the king to leave for a trip to Paris, but goes to Colomiers. The Prince of Cleves guesses about the plans of the Duke and sends a young nobleman of his entourage to follow him. Getting into the garden and approaching the window of the pavilion, the Duke sees Princess tying bows on a cane that belonged to him. Than she admires the painting, where he is depicted in a number of other military who took part in the siege of Metz. Duke takes a few steps, but touches the window frame. Princess turns to the noise, and seeing him immediately disappears. The next night the Duke again comes under the window of the pavilion, but she does not appear. He visits his sister Madame de Merkёr, living next door, and deftly leads the conversation to the fact that the sister invites him to accompany her to the Princess of Cleves. Princess is making every effort to ensure that no minutes would spend alone with the Duke.
Duke returns to Chambord, where the king and the court are located. Prince’s messenger arrives in Chambord before him and reports that the Duke has spent two nights in the garden, and then was in Colomiers with Madame de Merkёr. Prince can not bear misfortune, he starts to fever. 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. Princess swears to him that she did not have in mind to betray him. Prince is happy that his wife deserves the respect he felt for her, but could not recover from the shock and dies within few days. Realizing that it is her to blame for her husband's death, the Princess of Cleves feels to herself and to the Duke of Nemours burning hatred. She bitterly mourns her husband and the rest of life is going to act just as it would be nice for him if he were alive. Mindful of the fact that he expressed the fear that she might marry after his death the Duke of Nemours, she firmly decided never to do it.
The Duke of Nemours opens de Chartres his feelings for his niece and asks to help him to see her. Chartres readily agrees, because the Duke seems to him the most worthy contender for the hand of the Princess of Cleves. Duke declares his love to princess and says how he learned about her feelings for him, being a witness to her conversation with the prince. Princess of Cleves makes no secret that she loves the Duke, but refuses to marry him. She believes Duke to be guilty of the death of her husband, and firmly believes that a marriage with him is contrary to her duty.
Princess of Cleves goes to her distant tenure, and gets seriously ill. Recovering from illness, she moves to the monastery, and no one can convince her to return to the court. The Duke of Nemours goes to her himself, but the princess refuses to accept him. Sometimes she lives in the monastery, the rest of the time - in her possession. And her short life will be an example of unique virtues.