During a train ride, Pozdnyshev overhears a conversation concerning marriage, divorce and love. When a woman argues that marriage should not be arranged but based on true love, he asks "what is love?" and points out that, if understood as an exclusive preference for one person, it often passes quickly. Convention dictates that two married people stay together, and initial love can quickly turn into hatred. He then relates how he used to visit prostitutes when he was young, and complains that women's dresses are designed to arouse men's desires. He further states that women will never enjoy equal rights to men as long as men view them as objects of desire, but yet describes their situation as a form of power over men, mentioning how much of society is geared towards their pleasure and well-being and how much sway they have over men's actions.
After he meets and marries his wife, periods of passionate love and vicious fights alternate. She bears several children, and then receives contraceptives: "The last excuse for our swinish life -- children -- was then taken away, and life became viler than ever." His wife takes a liking to a violinist, Troukhatchevsky, and the two perform Beethoven's Kreutzer Sonata (Sonata No. 9 in A Major for piano and violin, Op. 47) together. Pozdnyshev complains that some music is powerful enough to change one's internal state to a foreign one. He hides his raging jealousy and goes on a trip, returns early, finds Troukhatchevsky and his wife together and kills his wife with a dagger. The violinist escapes: "I wanted to run after him, but remembered that it is ridiculous to run after one's wife's lover in one's socks; and I did not wish to be ridiculous but terrible."
Later acquitted of murder in light of his wife's apparent adultery, Pozdnyshev rides the trains seeking forgiveness from fellow passengers.