The end of 1867. Prince Lev Nikolaevich Myshkin arrives in St. Petersburg from Switzerland. He is twenty-six years old, the last of a noble noble family, orphaned early, fell ill with a serious nervous illness as a child, and was placed by his guardian and benefactor Pavlishchev in a Swiss sanatorium. He lived there for four years and now returns to Russia with unclear but big plans to serve her. On the train, the prince meets Parfen Rogozhin, the son of a wealthy merchant, who inherited a huge fortune after his death. From him, the prince first hears the name of Nastasya Filippovna Barashkova, the mistress of a certain wealthy aristocrat Totsky, whom Rogozhin is passionately passionate about.

Upon arrival, the prince with his modest bundle goes to the house of General Yepanchin, a distant relative of his wife, Elizabeth Prokofievna, is. The Epanchins family has three daughters - the eldest Alexandra, the middle Adelaide and the youngest, common favorite and beauty Aglaya. The prince amazes everyone with spontaneity, trustfulness, frankness and naivety, so extraordinary that at first he is received very cautiously, but with increasing curiosity and sympathy. It turns out that the prince, who seemed a simpleton, and to some cunning, is very intelligent, and in some things really deep, for example, when he talks about the death penalty he saw abroad. Here the prince also meets with the extremely proud ambassador of General Ganei Ivolgin, from whom he sees a portrait of Nastasya Filippovna. Her face of dazzling beauty, proud, full of contempt and hidden suffering, strikes him to the core.

The prince also learns some details: the seducer Nastasya Filippovna Totsky, trying to free herself from her and bearing plans to marry one of the Yepanchins' daughters, woos her for Ganya Ivolgin, giving seventy-five thousand as a dowry. Ghana is attracted by money. With their help, he dreams of breaking out into people and subsequently significantly increasing capital, but at the same time, the humiliating position does not give him rest. He would have preferred a marriage with Aglaya Yepanchina, with whom, perhaps, even a little in love (although here too he expects the possibility of enrichment). He expects a decisive word from her, making his further actions dependent on it. The prince becomes an involuntary mediator between Aglaya, who unexpectedly makes him his confidant, and Ganya, causing irritation and anger in this.

Meanwhile, the prince is offered to settle not somewhere else, namely in the Ivolgins' apartment. The prince does not have time to occupy the room provided to him and get to know all the inhabitants of the apartment, starting with the family of Ghani and ending with his sister's fiance as a young money-lender Ptitsyn and the master of incomprehensible occupations Ferdyshchenko, as two unexpected events occur. Suddenly, none other than Nastasya Filippovna appears in the house, who came to invite Ganya and his family for the evening. She is amused, listening to the fantasies of General Ivolgin, which only glow the atmosphere. Soon a noisy company appeared with Rogozhin at the head, who laid out eighteen thousand before Nastasya Filippovna. Something like bargaining is taking place, as if with her mockingly contemptuous participation: is it her, Nastasya Filippovna, for eighteen thousand? But Rogozhin is not going to retreat: no, not eighteen to forty. No, not forty - one hundred thousand! ..

For Gani’s sister and mother, what is happening is unbearably insulting: Nastasya Filippovna is a corrupt woman who should not be allowed into a decent house. For Ghani, she is the hope of enrichment. A scandal breaks out: the indignant sister of Gani Varvara Ardalionovna spits in his face, he is going to hit her, but the prince unexpectedly intervenes and receives a slap in the face from the furious Gani. "Oh, how you will be ashamed of your act!" - in this phrase all Prince Myshkin, all his incomparable meekness. Even at that moment he is compassionate to another, even to the offender. His next word addressed to Nastasya Filippovna: “Are you the way you imagined yourself now?” Will be the key to the soul of a proud woman who is deeply suffering from her shame and who loves the prince for recognizing her purity.

Conquered by the beauty of Nastasya Filippovna, the prince comes to her in the evening. A motley society has gathered here, starting with General Yepanchin, also passionate about the heroine, to the jester Ferdyshchenko. To the sudden question of Nastasya Filippovna whether she should marry Ganya, he answers negatively and thereby destroys the plans of Totsky present here. At half-past ten the bell blows and the previous company appears, headed by Rogozhin, who spreads out one hundred thousand wrapped in a newspaper in front of his chosen one.

And again, in the center is the prince, who is hurt by what is happening, he confesses his love to Nastasya Filippovna and expresses his readiness to marry her, “honest” and not “Rogozhinsky”. It suddenly turns out that the prince received a rather substantial inheritance from the dead aunt. However, the decision was made - Nastasya Filippovna was traveling with Rogozhin, and she threw the fatal bundle with one hundred thousand into the burning fireplace and invited Ghana to get them out of there. Ganya, with all her might, is holding back so as not to rush for the flashed money, he wants to leave, but falls without feelings. Nastasya Filippovna herself grabs a bundle with fireplace tongs and leaves money to Ghana as a reward for his torment (then they will be proudly returned to them).

Six months pass. The prince, having traveled around Russia, in particular on hereditary matters, and simply out of interest in the country, comes from Moscow to St. Petersburg. During this time, according to rumors, Nastasya Filippovna several times fled, almost from under the crown, from Rogozhin to the prince, stayed with him for some time, but then fled from the prince.

At the station, the prince feels someone's fiery look on himself, which languishes with his vague foreboding. The prince pays a visit to Rogozhin in his dirty green house, like a prison, on Gorokhovaya Street, during their conversation the prince is haunted by a garden knife lying on the table, he continually picks it up until Rogozhin finally picks it up in irritation he has it (then Nastasya Filippovna will be killed with this knife). In the house of Rogozhin, the prince sees on the wall a copy of the painting by Hans Holbein, which shows the Savior, just removed from the cross. Rogozhin says that he loves to look at her, the prince cries out in amazement that "... another person may still lose faith from this picture," and Rogozhin unexpectedly confirms this. They exchange crosses, Parthenus leads the prince to his mother for a blessing, since they are now like siblings.

Returning to his hotel, the prince at the gate suddenly notices a familiar figure and rushes after her to a dark narrow staircase. Here he sees the same as at the station, the sparkling eyes of Rogozhin, the knife brought in. At the same instant, a seizure of epilepsy occurs with the prince. Rogozhin runs away.

Three days after the seizure, the prince moves to Lebedev's cottage in Pavlovsk, where the Yepanchins family is also located and, according to rumors, Nastasya Filippovna. On the same evening, he gathers a large society of acquaintances, including the Yepanchins, who decided to visit the sick prince. Kolya Ivolgin, Gani’s brother, teases Aglaya with the “knight of the poor”, clearly hinting at her sympathy for the prince and provoking the painful interest of Aglaya’s mother Elizaveta Prokofievna, so her daughter is forced to explain that the verses depict a person who is able to have an ideal and, having believed in him, to give life for this ideal, and then with inspiration reads the very poem of Pushkin.

A little later, a company of young people appears, headed by a certain young man, Burdovsky, allegedly "the son of Pavlishchev." They seem to be nihilists, but only, according to Lebedev, “they went further, because primarily business ones.” A libel about the prince is read from the newspaper, and then they demand that he, as a noble and honest man, reward the son of his benefactor. However, Ganya Ivolgin, whom the prince instructed to take up this matter, proves that Burdovsky is not at all Pavlishchev’s son. The company retreats in embarrassment, only one of them remains in the spotlight - the consumptive Ippolit Terentyev, who, asserting himself, begins to “oratory”. He wants to be pitied and praised, but even ashamed of his openness, his inspiration is replaced by fury, especially against the prince. Myshkin, on the other hand, listens attentively to everyone, pities everyone and feels himself in front of everyone to blame.

A few days later the prince visits the Epanchins, then the whole Epanchins family, together with Prince Eugene Pavlovich Radomsky, who is caring for Aglaia, and Prince Shch., The bridegroom of Adelaide, go for a walk. At the station, not far from them, another company appears, among which Nastasya Filippovna. She familiarly turns to Radomsky, informing him of the suicide of his uncle, who wasted a large sum of state. Everyone is outraged by the provocation. The officer, a friend of Radomsky, remarks in indignation that “you just need a whip here, otherwise you won’t take anything with this creature!”, In response to his insult, Nastasya Filippovna cut a face from her hand with a cane cut to blood. The officer is about to hit Nastasya Filippovna, but Prince Myshkin is holding him back.

At the celebration of the Prince’s birthday, Ippolit Terentyev reads “My necessary explanation” written by him - an amazingly deep confession of a young man who almost did not live, but who changed his mind a lot, who was doomed by his illness to premature death. After reading, he commits suicide, but the capsule is not in the gun. The prince protects Hippolytus, painfully afraid to seem ridiculous, from attacks and ridicule.

In the morning on a date in the park Aglaya invites the prince to become her friend. The prince feels that he truly loves her. A little later in the same park there is a meeting between the prince and Nastasya Filippovna, who kneels before him and asks him if he is happy with Aglaya, and then disappears with Rogozhin. It is known that she writes letters to Aglaya, where she persuades her to marry the prince.

A week later, the prince was formally declared the bridegroom of Aglaya. High-ranking guests are invited to the Yepanchins on a kind of “bride” of the prince. Although Aglaya believes that the prince is incomparably higher than all of them, the hero, precisely because of her partiality and intolerance, is afraid to make the wrong gesture, is silent, but then painfully inspired, speaks a lot about Catholicism as anti-Christianity, declares all his love, breaks a precious Chinese vase and falls in another fit, making a painful and awkward impression on those present.

Aglaya makes an appointment to Nastasya Filippovna in Pavlovsk, to which she comes with the prince. In addition to them, only Rogozhin is present. The “Proud Young Lady” asks sternly and hostilely what right Nastasya Filippovna has to write letters to her and generally interfere with her and the prince’s personal life. Offended by the tone and attitude of the rival, Nastasya Filippovna, in a fit of revenge, calls on the prince to stay with her and drives Rogozhin. The prince is torn between two women. He loves Aglaya, but he also loves Nastasya Filippovna - love-pity. He calls her crazy, but unable to leave her. The prince’s condition is getting worse, he is more and more immersed in mental turmoil.

The wedding of the prince and Nastasya Filippovna is planned. This event is surrounded by various kinds of rumors, but Nastasya Filippovna seemed to be happily preparing for him, writing out her outfits and being either in enthusiasm or causeless sadness. On the wedding day, on the way to the church, she suddenly rushes to Rogozhin, who is standing in the crowd, who picks her up in her arms, gets into the carriage and takes her away.

The next morning after her escape, the prince arrives in Petersburg and immediately leaves for Rogozhin. He is not at home, but the prince is wondering if Rogozhin seems to be looking at him from behind a curtain. The prince walks on acquaintances Nastasya Filippovna, trying to find out something about her, returns to Rogozhin’s house several times, but to no avail: no, nobody knows anything. All day the prince wanders through the sultry city, believing that Parfen will certainly appear. This is what happens: on the street he is met by Rogozhin and in a whisper asks to follow him. In the house, he leads the prince to a room where in an alcove on a bed under a white sheet, furnished with bottles of Zhdanov liquid, so as not to smell the decay, lies dead Nastasya Filippovna.

The prince and Rogozhin spend a sleepless night together over the corpse, and when the door is opened the next day in the presence of the police, they find Rogozhin rushing about in delirium and calming him down, who already understands nothing and does not recognize anyone. Events completely destroy the psyche of Myshkin and finally turn him into an idiot.