Alexey Ivanovitch returns to Roulettenburg, a German resort, after two weeks in Paris. He is a tutor in the family of a Russian general who comes to the resort to repair his dwindling fortune. The General woos an apparently wealthy young Frenchwoman, Mademoiselle Blanche. Polina, the General’s stepdaughter, is attracted to Mademoiselle Blanche’s alleged distant relative, the Marquis de Grieux. Alexey is Polina’s creature; he loves her and accepts any humiliation at her hands.

Alexey goes to the casino with money Polina gives him. After winning a tidy amount, he feels that his stay in Roulettenburg will affect his life seriously. Believing that he cannot lose at the gambling tables, Alexey tells Polina that hereafter he will gamble only for himself. Polina, however, aware of her power over Alexey, easily persuades him to share his winnings with her.

An affluent young English capitalist, Astley, comes to Roulettenburg and, much to the General’s discomfort, diverts the attentions of Mlle Blanche, who is growing tired of waiting for the General’s old aunt to die. The General telegraphs Moscow every day to inquire about the condition of the old lady, who, he is sure, will leave him a fortune.

It is soon evident that Astley is in love with Polina. Alexey, suspecting the French pair to be impostors, wants to get away from the machinations of Roulettenburg existence, but his love for Polina holds him. At the casino he loses a large amount of Polina’s money; his possession of the money arouses renewed interest in the General on the part of Mlle Blanche. The General, it seems, is deeply in debt to de Grieux.

Unable to win with Polina’s money, Alexey offers to win with his own and to lend her whatever she wants. Alexey hopes that he can win Polina by becoming wealthy through gambling. He confesses his ardent love for her, and when he tells her that he can even commit murder for her, she impishly orders him to speak in French to a stuffy German baroness who is passing by with her husband. After Alexey brashly insults the Germans, he is discharged by the General, despite his plea that he was mentally aberrant during the escapade. Alexey manages to maintain his self-respect when he tells the General, who apologizes to the baron for Alexey’s behavior, that he is capable of making his own apologies, that as the son of a nobleman he objects to the General’s patronizing treatment. The General, fearful of the consequences of Alexey’s further impetuosities, unsuccessfully tries to mollify the youth.

De Grieux, as mediator, tells Alexey that any further indiscretion on his part might spoil the chances of the General’s marriage to Mlle Blanche. He also promises that the General will reemploy Alexey soon and will continue, meanwhile, to pay him his salary. Alexey, however, chooses Astley to be his second in a duel with the baron. De Grieux then produces a letter from Polina asking Alexey to drop the matter. The young man obeys, although he knows for certain that Polina loves de Grieux.

Astley indirectly confirms Alexey’s suspicions that Mlle Blanche and de Grieux are adventurers. During previous exploits at Roulettenburg, Mlle Blanche made advances to the baron and, at the direction of the baroness, was escorted out of the casino by the police. Alexey suspects the General of being indebted somehow to Mlle Blanche, and Polina of being involved with the French couple.

The General’s old aunt, Antonida Tarasevitcheva, arrives from Moscow with a large retinue. Quite alive, she wickedly chides the General about his urgent solicitations and criticizes him for squandering his children’s inheritance. The General is visibly shocked by her arrival. Accompanied by the General’s party, the old lady visits the casino and wins fabulously at the gaming tables. In her triumph she gives money to her servants and to beggars.

Polina becomes more of an enigma to Alexey when she has him deliver a letter to Astley. Despite the General’s pleas to the young tutor to prevent Antonida from gambling away her fortune, Alexey and the old lady frequent the casino together. Obsessed with the fever to win, she loses heavily. When she prepares to return to Moscow, she invites Polina to return with her, but Polina declines. Antonida, unable to resist one last try at the gambling tables, again loses heavily. She converts bonds into cash and again loses. The old lady now possesses nothing but land and the houses on it; she borrows money from Astley in order to return to Moscow.

The General’s inheritance having been lost at roulette, Mlle Blanche and de Grieux break off relations with him and prepare to leave Roulettenburg. The General is a ruined man. Polina is distracted by her impending loss of de Grieux, but she is shaken out of her infatuation when de Grieux offers her consolation money from the proceeds of the General’s property, which was mortgaged to de Grieux. In distress, Polina turns to Alexey, who goes to the casino and wins a fortune for her to hurl in de Grieux’s face. She spends the night with Alexey in his hotel room. The next morning she takes his money, then throws it in his face. She flees to Astley. Alexey goes with Mlle Blanche to Paris, where he lives with her while she spends his winnings. Tired of the life of an adventuress, Mlle Blanche, persuaded by Alexey, decides to marry the General.

Now a confirmed gambler, Alexey returns to the gambling tables of the German resort towns. Once he goes to jail for debt. In Homburg he sees Astley, who tells him that Polina, recuperating from an illness, is in Switzerland with Astley’s family. Meanwhile the General dies of a stroke in Paris, and Mlle Blanche receives his inheritance from Antonida, who dies in Moscow. Alexey regretfully reminds Astley of Polina’s infatuation for de Grieux and is momentarily hopeful when Astley tells him that Polina sent him to Homburg to bring Alexey back to her. Alexey knows that he has no choice, really—he has given his heart and soul to gambling.