The novel portrays the murder of a miserly, aged pawnbroker and her younger sister by a destitute Saint Petersburg student named Raskolnikov, and the emotional, mental, and physical effects that follow.

After falling ill with fever and lying bedridden for days, Raskolnikov is overcome with paranoia and begins to imagine that everyone he meets suspects him of the murder; the knowledge of his crime eventually compromises his sanity. Prior to the crime he meets, in a tavern, a down-on-his luck former civil servant — Marmeladov, who tells him of his own desperate circumstances — including the circumstances of his only daughter Sonya, who has been forced to become a prostitute to feed her stepbrother and sisters. Raskolnikov becomes the family's benefactor after the death of Marmeladov and becomes fascinated with Sonya. This relationship can be interpreted as an allegory of God's love for fallen humanity — and the redemptive power of that love — but only after Raskolnikov has confessed to the murder and been sent to imprisonment in Siberia. It is there that he realises that he is capable of love — and that he loves Sonya. Apart from Raskolnikov's fate, the novel, with its long and diverse list of characters, deals with themes including charity, family life, atheism, alcoholism, and revolutionary activity, with Dostoevsky highly critical of contemporary Russian society.

Raskolnikov theorized that there are two types of men, ordinary and extraordinary. He believed that since he was of the latter or a "super-human," that he could justifiably perform what society considered a despicable act — the killing of the pawn broker — if it led to his being able to do more good through the act. Throughout the book there are examples: he mentions Napoleon many times, thinking that for all the blood he spilled, he was not morally culpable, as he was "above" the conventions of society. Raskolnikov believed that he could transcend this moral boundary by killing the money lender, gaining her money, and using it to do good. He argued that had Isaac Newton or Johannes Kepler needed to kill one or even a hundred men in order to enlighten humanity with their laws and ideas, it would be worth it. Thus he is thrown into a depressed state over the death of the pawnbroker's sister. Never at any time in the novel is he repentant over the death of the pawnbroker.

Raskolnikov's real punishment is not the labour camp he is condemned to, but the torment he endures throughout the novel. This torment manifests itself in the aforementioned paranoia. He is unable to engage in 'normal' human relationships and it is only when imprisoned and away from the distraction of Petersburg that he is able to realise that he too is able to fully love another — Sonya and he is then able to engage with the world once more. It is the resolution of the inner battle within himself — between his inhuman philosophy and his distinctly human character — that allows his redemption.