The book is the unsent confession of a nameless man, a minor official who has retreated from St. Petersburg society into a shabby room he calls his corner. He opens by announcing that he is sick, spiteful, and unattractive, that his liver is bad and he will not see a doctor out of pure spite, and that he has festered like this for twenty years. The voice is contradictory by design: it boasts and grovels, asserts and retracts, and dares the reader to despise it.
The first part is a long argument with imagined opponents. The narrator claims that to be too conscious is a real, thorough-going illness, because heightened awareness dissolves every impulse into hesitation while the dull man of action moves freely. From this he mounts an attack on the rational, utilitarian creed of his day, the belief that once human desires are reduced to a formula, people will behave sensibly and a flawless society can be built.
His rebuttal is that human beings will not be reduced. A person confronted with a final, irrefutable truth, neat as twice two makes four, will spit at it precisely because it leaves no room for choosing. People love suffering, chaos, and their own caprice; they will sabotage the perfect outcome to assert that they are persons and not piano-keys. He would rather inhabit a poor hut he can curse than a crystal palace he is told to be grateful for, because freedom matters more to him than any guaranteed good.
The second part drops the argument for memory. At twenty-four the narrator is already isolated and resentful. After a humiliating evening forcing himself on former schoolmates who do not want him, he follows them to a brothel and there meets Liza, a young prostitute. To wound her and to perform his own superiority, he delivers a sermon on the ruined life ahead of her, and to his discomfort the speech reaches her. He gives her his address almost as a dare.
When Liza actually comes to him, his fear of being seen in his squalor curdles into rage. He confesses that he had only been amusing himself at her expense and lashes her with contempt; she understands that he is the truly unhappy one and embraces him, which only stokes a final cruelty in him before she leaves. He half-runs after her into the falling snow, then lets her go, talking himself into the idea that her wound will purify her. Years later, still writing from underground, he admits the whole memory is evil and that he can no longer tell suffering from spite.