After four years spent in Switzerland, where he was treated for epilepsy at a sanatorium, Prince Myshkin returns to St. Petersburg. On the train, the threadbare shabbiness of his clothing attracts the attention of the other passengers. One of these, Parfen Rogozhin, begins to question him. By the time they reach St. Petersburg, the prince and Rogozhin are well informed about each other, and Rogozhin offers to take the prince to his home and to give him money.

Myshkin, however, first wants to introduce himself to General Epanchin, whose wife is distantly related to him. At the Epanchin home, he meets the general and his secretary, Ganya, who invites him to become one of his mother’s boarders. The prince interests the general, who gives him some money, and fascinates the general’s wife and three daughters. His lack of sophistication, his naïveté, and his frankness charm and amuse the family. Soon they begin to call him “the idiot,” half in jest, half in earnest, but he remains on good terms with them.

Ganya, a selfish young man given to all kinds of scheming, wants to marry the beautiful Aglaya Epanchin, chiefly for her money. At the time, he is also involved in an affair with the notorious Natasya, an attractive young woman who lives under the protection of a man she does not love. Extremely emotional and neurotic, Natasya is really innocent of the sins with which she is charged. Myshkin realizes her helplessness and pities her. At a drinking party one night soon after his arrival, he asks her to marry him, saying that he received an unexpected inheritance. She refuses, declaring that she has no desire to cause his ruin. Instead she goes with Rogozhin, who brings her a hundred thousand rubles. More than ever, Natasya becomes the object of spirited controversy among the Epanchins and their circle. Myshkin alone remains unembittered and always kindhearted. Ganya and Rogozhin pour out their troubles to him, bare the sordid and shameless nature of their lives, and swear undying friendship to him. They nevertheless distrust Myshkin and plot against him. When Natasya leaves Rogozhin, he swears that he will kill “the idiot” because he is sure that Natasya fled from him because she really loves Myshkin.

Myshkin then becomes the victim of an extortion attempt. During a violent, repugnant scene, at which the Epanchins are present, he successfully refutes the charge that he deprived Rogozhin’s supposed illegitimate son of his rightful inheritance. Having proved that the individual who sought the money is not the illegitimate son, he then offers to give money to the extortionist and to become his friend. This action disgusts Madame Epanchin, who considers the prince more of an idiot than ever.

Meanwhile, Aglaya falls in love with Myshkin, but she continues to treat him scornfully and at first refuses to admit that she is in love with him. When her true feelings at last become apparent, Madame Epanchin gives reluctant consent to their betrothal and plans an evening party to introduce Myshkin to St. Petersburg society. Worried lest he should commit some social blunder, she and her daughter advise him to sit quietly and to say nothing during the evening. At the party, however, Madame Epanchin herself draws out the prince, so that he is soon launched on one of his wild and peculiar conversations. The staid, conservative guests are astounded. In the midst of the discussion, he knocks over a huge and priceless vase, then stares at the debris like “an idiot.” A few minutes later, he falls into an epileptic fit and has to be carried...