Prince Myshkin is on a train pulling into St. Petersburg, Russia. He is sitting next to Rogozhin, a young man with a “malicious smile,” and Lebedev, a foolish clerk. Myshkin has been receiving treatment for epilepsy in Switzerland for almost five years, and has no money; Rogozhin, on the other hand, has just inherited an enormous fortune. Rogozhin has been trying to seduce the beautiful Nastasya Filippovna, and is going to see her that night.
Myshkin goes to the house of his distant relative, Mrs. Lizaveta Prokofyevna Epanchin. Lizaveta and her husband, General Epanchin, are wealthy and well-respected. They have three unmarried daughters in their early 20s: Alexandra, Adelaida, and Aglaya. Myshkin and General Epanchin meet in Epanchin’s office. At first Epanchin is suspicious of Myshkin, but then comes to like him, offering him a job, some money, and a place to stay with his associate, Ganya. Ganya may be about to marry Nastasya; Totsky, Nastasya’s wealthy guardian who sexually abused her as a teenager, has offered an enormous sum for her dowry. Ganya seems a little hesitant about the engagement. After this conversation, Myshkin speaks with the four Epanchin women and greatly charms them. Ganya asks Myshkin to help him express his love for Aglaya one last time, but Aglaya coldly rejects him.
Myshkin goes to Ganya’s family’s apartment, where he meets Ganya’s father General Ivolgin, his mother Nina, his brother Kolya, and his sister Varya. They have one other tenant, an unpleasant person named Ferdyshchenko. Varya’s suitor, Ptitsyn, is also there. A fight breaks over the prospect of Ganya’s potential marriage to Nastasya, which Nina and Varya oppose because Ganya is clearly just doing it for money. At that moment, Nastasya herself arrives. She attempts to be friendly with the Ivolgins, but ends up embarrassing General Ivolgin by revealing that an anecdote he told about himself was actually stolen from a recent newspaper article. A huge, rowdy group of people enter, including Rogozhin, who offers Nastasya 100,000 roubles for her hand in marriage.
Later that same evening, Myshkin invites himself to Nastasya’s birthday party, having failed to get the drunk and wayward General Ivolgin to take him there. At the party, Nastasya insists they play a game wherein every person goes around and says the worst thing they’ve ever done. However, none of the stories are that shocking, and some even contain boasts about good deeds embedded within them. Nastasya quickly announces that she is bored.
Rogozhin arrives, and places the 100,000 roubles he promised Nastasya on the table. Nastasya comments that she has a lot of suitors now, but as soon as she leaves behind the luxurious lifestyle Totsky provides, no one will want her anymore. Myshkin says he would, and also notes that he’s due to inherit 1.5 million roubles and shyly agrees to marry Nastasya when Ferdyshchenko suggests the engagement. The party erupts in joy, toasting Myshkin’s imminent fortune and well as his engagement to Nastasya. However, Nastasya soon notes that she might still choose Rogozhin. She throws the 100,000 roubles into the fire, tells Ganya to get them, and leaves.
Myshkin does not end up receiving his full inheritance, only a small fraction of it. Nastasya keeps repeatedly abandoning Rogozhin before agreeing to marry him again. In the beginning of June, the Epanchins leave for their dacha in Pavlovsk. Back in St. Petersburg, Myshkin goes to Rogozhin’s decidedly gloomy house and beholds Rogozhin’s copy of Holbein’s painting “The Dead Christ.” Myshkin is horrified by it, remarking that it could turn a man into an atheist. After Myshkin leaves the house, he feels Rogozhin’s eyes on him. Becoming increasingly delirious, he encounters Rogozhin on the stairway in his hotel. Rogozhin tries to stab him, but at this point Myshkin starts having an epileptic fit, and Rogozhin runs away. Myshkin tumbles down the stairs and injures his head in the midst of the fit, but is taken to a doctor and survives the fall.
Lebedev takes Myshkin to be nursed back to health at his dacha. The Epanchin women come to visit, in a state of great concern about Myshkin’s health. Kolya notes that Aglaya won’t stop talking about “the poor knight,” a character from Cervantes’ Don Quixote and a recent poem by Pushkin whose penchant for unconditional love seems to represent Myshkin.
During the Epanchins’ visit, four young men barge into Lebedev’s dacha: Burdovsky, Keller, Ippolit, and Doktorenko. They declare that Burdovsky is the illegitimate son of Myshkin’s late benefactor, Pavlishchev, and that Myshkin has “stolen” Burdovksy’s inheritance. Calmly and graciously, Myshkin proves that they are lying, but offers them money anyway. Humiliated, Burdovsky refuses. Meanwhile, Mrs. Epanchin is getting increasingly worried that Aglaya and Myshkin are going to get married, although Aglaya still often speaks about Myshkin in an insulting way, calling him a “little freak” and an “idiot.”
At a gathering at the Epanchins’, Evgeny, a young friend of the family, discusses whether there could ever be a truly Russian form of liberalism. Myshkin then discusses criminals. Aglaya declares that she will never marry Myshkin because he is a “ridiculous man,” and Mrs. Epanchin suggests they all go to the vauxhall to hear some music before a fight breaks out. At the vauxhall, Nastasya tells Evgeny in a rather jolly tone that his uncle is embroiled in a scandal involving missing government funds and has killed himself. A passing officer comments that Nastasya should be whipped, at which point Nastasya grabs a whip and whacks the officer. Myshkin also gets involved, trying to defend Nastasya.
Rogozhin informs Myshkin that Nastasya wants him and Aglaya to get married so they can both be happy. Myshkin is horrified by this. However, he then remembers it is his birthday and transitions into an unexpectedly happy mood. He suggests they go back to Lebedev’s dacha to drink champagne. There, so many people have been waiting to see Myshkin that an impromptu surprise party has begun.
At the party, Ippolit, who is terminally ill with tuberculosis, gathers everyone together and retrieves a document from his pocket to read. It is entitled “A Necessary Explanation,” and is a speech about his life, his illness, and his thoughts on nihilism. The document is melodramatic long-winded. he audience, who didn’t want to hear it in the first place, quickly grow bored. Once the reading is finally over, Ippolit declares he is going to shoot himself, though few people believe him. He tries, but it turns out the cap was not on the gun, and to his mortification he survives completely unharmed.
At her request, Myshkin meets Aglaya in the park early the next morning. She expresses frustration with her life and asks Myshkin to help he run away from home. She then reveals that Nastasya has been writing her letters.
The same day, Lebedev realizes that his wallet has gone missing, and he realizes that the prime suspects are Ferdyshchenko and his dear friend General Ivolgin, who has only recently been released from debtor’s prison. He decides to track Ferdyshchenko down in St. Petersburg, despite Myshkin expressing doubts that Ferdyshchenko is the real thief.
Later, Aglaya shows Myshkin the letters Nastasya has written to her, in which Nastasya declares that she is in love with Aglaya but says that she hopes Aglaya and Myshkin get married. Meanwhile, news spreads that Myshkin and Aglaya are engaged, when in fact this arrangement is certainly not official, and possibly not even happening at all. Lebedev returns from St. Petersburg and at first spends every second with Ivolgin; however, the two then have a fight and stop talking. Speaking privately with Myshkin, Ivolgin expresses his annoyance that Lebedev has disrespected him, and tells an obviously false story about meeting Napoleon as a boy. Shortly after, Ivolgin suffers a stroke.
Mrs. Epanchin is hysterically upset about the idea that Myshkin and Aglaya might get married. Aglaya becomes increasingly rude to Myshkin and eventually declares that she will never marry him. This has a strangely positive effect on Myshkin, putting him in a happy mood. The Epanchins arrange a gathering in which they hope to introduce Myshkin to their high society friends. Aglaya sarcastically tells Myshkin that he should break Mrs. Epanchin’s beloved, extremely expensive Chinese vase during the event.
At the beginning of the gathering Myshkin stays quiet, and makes sure that he is far away from the vase. However, after one of the guests mentions that Pavlishchev converted to Catholicism, Myshkin goes on a wild rant about how the Catholic Church is “unchristian” and worse than atheism. He becomes so impassioned that he travels toward the vase without noticing and knocks it over. He fears that Mrs. Epanchin will be devastated, but she actually laughs it off, saying it doesn’t matter.
Shortly after, Nastasya, Aglaya, Myshkin, and Rogozhin all meet at Nastasya’s friend Darya’s dacha. Aglaya curses Nastasya for interfering in her life, and Nastasya replies that she could take Myshkin if she wanted to. Aglaya runs away, but before Myshkin can go after her Nastasya faints in his arms. Before he knows it, he finds himself banned from speaking to Aglaya and engaged to Nastasya again.
Rumors fly about what Myshkin did to Aglaya—many of them untrue—and even his closest friends are highly disapproving. Myshkin manages to explain to Evgeny that he loves both women and never intended to choose Nastasya over Aglaya. The night before the wedding, Nastasya expresses horror at the idea that she will ruin Myshkin’s innocence. The next day, just as the ceremony begins, Nastasya sees Rogozhin in the crowd and runs to him, demanding that he take her away.
Myshkin is largely unperturbed by being stood up at the altar, but soon after goes to St. Petersburg to try and find Nastasya and Rogozhin. After looking all over the city, he eventually runs into Rogozhin, who takes him to his gloomy house. Rogozhin shows Nastasya’s dead body to Myshkin, confessing that he stabbed her. The two speak for a while, and then each fall into a separate delirium. The police come and arrest Rogozhin he is sentenced to 15 years’ hard labor in Siberia. Myshkin, meanwhile, goes back to the Swiss Institute for more treatment, this time paid for by Evgeny. Aglaya marries a man who pretends to be an exiled Polish count but is in reality no such thing. She converts to Catholicism and becomes estranged from her family.
