Dmitri Gurow, a bored bank clerk weary of his marriage and accustomed to fleeting romantic adventures, embarks on an affair with the young Anna Sergeyevna during a vacation at the Black Sea. When she, the shy lady with the little dog, eventually returns home to her ailing husband, Gurow goes back to his family in Moscow, expecting that the memory of her will fade away—just like all his previous flings. However, he soon realizes that his encounter with her has completely transformed him, making it impossible for him to return to his old life. He follows her to the provincial town of S. to see her again. What began as a holiday flirtation now develops into something neither of them anticipated: a passionate love that defies all societal obstacles.