Dmitri Gurov works in a Moscow bank. He is nearing 40, married, and has a daughter and two sons. Unhappy in his marriage and the monotony and meaninglessness of his life, he is frequently unfaithful and considers women to be of "a lower race". While vacationing in Yalta, he sees a young woman walking along the seafront with her little Pomeranian, and endeavors to make her acquaintance. The lady, Anna Sergeyevna, is also unhappily married and vacationing without her husband. Anna and Dmitri soon commence an affair, and spend most of their time together, often walking and taking drives to the nearby village of Oreanda. Though she is expecting her husband to come to Yalta, he eventually sends word for her to come home, saying that something is wrong with his eyes. Gurov sees her off at the station. As they part, both feel that they will never see each other again, and thus their affair is over.
Returning to Moscow, to his loveless marriage and his daily routine, working by day and socializing by night, Gurov expects to soon forget young Anna, but to his surprise, her memory haunts him. Unexpectedly, he falls deeply in love for the first time, after many affairs and just as he is approaching middle age. He feels that he must see Anna, despite the obvious complications. On the ruse of going to St. Petersburg to attend to personal business, he sets off to Anna's hometown to find her. Learning the location of the family's residence from a hotel porter, he finds the house, only to realize that it would be unwise to intrude. In despair, he rationalizes that Anna has probably forgotten him and found someone else, and heads back to his hotel.
In the evening, he remembers having seen a sign earlier in the day announcing the opening performance of The Geisha. Reasoning that Anna and her husband might attend, he goes to the theater. The couple enters and he watches intently. When the husband goes out for a smoke during the first interval, Gurov greets Anna, who is bewildered and runs from him. After following her through the theater, he confronts her and she confides that she has been thinking of him constantly. Frightened, she begs him to leave and promises to see him in Moscow.
Anna makes excuses to travel to Moscow, telling her husband that she is going there to see a doctor, which he "believes and does not believe". The pair are now fully aware that for the first time in their lives they have actually fallen in love, and they both wonder how they might overcome the many challenges that face them and achieve their fervent wish to spend their lives together. They desperately try to come up with a plan, but the story ends without offering a resolution:
"They … talked of how to avoid the necessity for secrecy, for deception, for living in different towns and not seeing each other for long stretches of time … and it was clear to both of them that … the most complicated and difficult part of their journey was just beginning."
