Rodion Romanovich Raskolnikov, a former law student, lives in extreme poverty in a tiny, rented room in Saint Petersburg. Isolated and antisocial, he has abandoned all attempts to support himself, and is brooding obsessively on a scheme he has devised to murder and rob an elderly pawn-broker. On the pretext of pawning a watch, he visits her apartment, but remains unable to commit himself. Later in a tavern he makes the acquaintance of Semyon Zakharovich Marmeladov, a drunkard who recently squandered his family's little wealth. Marmeladov tells him about his teenage daughter, Sonya, who has chosen to become a prostitute in order to support the family. The next day Raskolnikov receives a letter from his mother in which she describes the problems of his sister Dunya, who has been working as a governess, with her ill-intentioned employer, Svidrigailov. To escape her vulnerable position, and with hopes of helping her brother, Dunya has chosen to marry a wealthy suitor, Luzhin, whom they are coming to meet in Petersburg. Details in the letter suggest that Luzhin is a conceited opportunist who is seeking to take advantage of Dunya's situation. Raskolnikov is enraged at his sister's sacrifice, feeling it is the same as what Sonya felt compelled to do. Painfully aware of his own poverty and impotence, his thoughts return to his idea. A further series of internal and external events seem to conspire to compel him toward the resolution to enact it.
In a state of extreme nervous tension, Raskolnikov steals an axe and makes his way once more to the old woman's apartment. He gains access by pretending he has something to pawn, and then attacks her with the axe, killing her. He also kills her half-sister, Lizaveta, who happens to stumble upon the scene of the crime. Shaken by his actions, he steals only a handful of items and a small purse, leaving much of the pawn-broker's wealth untouched. Due to sheer good fortune, he manages to escape the building and return to his room undetected.
In a feverish, semi-delirious state Raskolnikov conceals the stolen items and falls asleep exhausted. He is greatly alarmed the next morning when he gets a summons to the police station, but it turns out to be in relation to a debt notice from his landlady. When the officers at the bureau begin talking about the murder, Raskolnikov faints. He quickly recovers, but he can see from their faces that he has aroused suspicion. Fearing a search, he hides the stolen items under a building block in an empty yard, noticing in humiliation that he hasn't even checked how much money is in the purse. Without knowing why, he visits his old university friend Razumikhin, who observes that Raskolnikov seems to be seriously ill. Finally he returns to his room where he succumbs to his illness and falls into a prolonged delirium.
When he emerges several days later he finds that Razumikhin has tracked him down and has been nursing him. Still feverish, Raskolnikov listens nervously to a conversation between Razumikhin and the doctor about the status of the police investigation into the murders: a muzhik called Mikolka, who was working in a neighbouring flat at the time, has been detained, and the old woman's clients are being interviewed. They are interrupted by the arrival of Luzhin, Dunya's fiancé, who wishes to introduce himself, but Raskolnikov deliberately insults him and kicks him out. He angrily tells the others to leave as well, and then sneaks out himself. He looks for news about the murder, and seems almost to want to draw attention to his own part in it. He encounters the police official Zamyotov, who was present when he fainted in the bureau, and openly mocks the young man's unspoken suspicions. He returns to the scene of the crime and re-lives the sensations he experienced at the time. He angers the workmen and caretakers by asking casual questions about the murder, even suggesting that they accompany him to the police station to discuss it. As he contemplates whether or not to confess, he sees Marmeladov, who has been struck mortally by a carriage. He rushes to help and succeeds in conveying the stricken man back to his family's apartment. Calling out for Sonya to forgive him, Marmeladov dies in his daughter's arms. Raskolnikov gives his last twenty five roubles (from money sent to him by his mother) to Marmeladov's consumptive widow, Katerina Ivanovna, saying it is the repayment of a debt to his friend.
Feeling renewed, Raskolnikov calls on Razumikhin, and they go back together to Raskolnikov's building. Upon entering his room Raskolnikov is deeply shocked to see his mother and sister sitting on the sofa. They have just arrived in Petersburg and are ecstatic to see him, but Raskolnikov is unable to speak, and collapses in a faint.
Razumikhin tends to Raskolnikov, and manages to convince the distressed mother and sister to return to their apartment. He goes with them, despite being drunk and rather overwhelmed by Dunya's beauty. When they return the next morning Raskolnikov has improved physically, but it becomes apparent that he is still mentally distracted and merely forcing himself to endure the meeting. He demands that Dunya break with Luzhin, but Dunya fiercely defends her motives for the marriage. Mrs Raskolnikov has received a note from Luzhin demanding that her son not be present at any future meetings between them. He also informs her that he witnessed her son give the 25 rubles to "an unmarried woman of immoral behavior" (Sonya). Dunya has decided that a meeting, at which both Luzhin and her brother are present, must take place, and Raskolnikov agrees to attend that evening along with Razumikhin. To Raskolnikov's surprise, Sonya suddenly appears at his door. Timidly, she explains that he left his address with them last night, and that she has come to invite him to attend her father's funeral. As she leaves, Raskolnikov asks for her address and tells her that he will visit her soon.
At Raskolnikov's behest, Razumikhin takes him to see the detective Porfiry Petrovich, who is investigating the murders. Raskolnikov immediately senses that Porfiry knows that he is the murderer. Porfiry, who has just been discussing the case with Zamyotov, adopts an ironic tone during the conversation. He expresses extreme curiosity about an article that Raskolnikov wrote some months ago called 'On Crime', in which he suggests that certain rare individuals—the benefactors and geniuses of mankind—have a right to 'step across' legal or moral boundaries if those boundaries are an obstruction to the success of their idea. Raskolnikov defends himself skillfully, but he is alarmed and angered by Porfiry's insinuating tone. An appointment is made for an interview the following morning at the police bureau.
Leaving Razumikhin with his mother and sister, Raskolnikov returns to his own building. He is surprised to find an old artisan, whom he doesn't know, making inquiries about him. Raskolnikov tries to find out what he wants, but the artisan says only one word – "murderer", and walks off. Petrified, Raskolnikov returns to his room and falls into thought and then sleep. He wakes to find another complete stranger present, this time a man of aristocratic appearance. The man politely introduces himself as Arkady Ivanovich Svidrigailov.
Svidrigailov indulges in an amiable but disjointed monologue, punctuated by Raskolnikov's terse interjections. He claims to no longer have any romantic interest in Dunya, but wants to stop her from marrying Luzhin, and offer her ten thousand roubles. Raskolnikov refuses the money on her behalf and refuses to facilitate a meeting. Svidrigailov also mentions that his wife, who defended Dunya at the time of the unpleasantness but died shortly afterwards, has left her 3000 rubles in her will.
The meeting with Luzhin that evening begins with talk of Svidrigailov—his depraved character, his presence in Petersburg, the unexpected death of his wife and the 3000 rubles left to Dunya. Luzhin takes offence when Dunya insists on resolving the issue with her brother, and when Raskolnikov draws attention to the slander in his letter, he becomes reckless, exposing his true character. Dunya tells him to leave and never come back. Now free and with significant capital, they excitedly begin to discuss plans for the future, but Raskolnikov suddenly gets up and leaves, telling them, to their great consternation, that it might be the last time he sees them. He instructs the baffled Razumikhin to remain and always care for them.
He proceeds to Sonya's place. She is gratified that he is visiting her, but also frightened of his strange manner. He asks a series of merciless questions about her terrible situation and that of Katerina Ivanovna and the children. Raskolnikov begins to realize that Sonya is sustained only by her faith in God. She passionately reads to him the story of the raising of Lazarus from the Gospel of John. His fascination with her, which had begun at the time when her father spoke of her, increases and he sees that they must face the future together. As he leaves he tells her that he will come back tomorrow and tell her who killed her friend Lizaveta.
When Raskolnikov presents himself for his interview, Porfiry resumes and intensifies his insinuating, provocative, ironic chatter, without ever making a direct accusation. With Raskolnikov's anger reaching fever pitch, Porfiry hints that he has a 'little surprise' for him behind the partition in his office, but at that moment there is a commotion outside the door and a young man (Mikolka the painter) bursts in, followed by some policemen. To both Porfiry and Raskolnikov's astonishment, Mikolka proceeds to loudly confess to the murders. Porfiry doesn't believe the confession, but he is forced to let Raskolnikov go. Back at his room Raskolnikov is horrified when the old artisan suddenly appears at his door. But the man bows to him and asks for forgiveness: he had been Porfiry's 'little surprise', and had heard Mikolka confess. He had been one of those present when Raskolnikov returned to the scene of the murders, and had reported his behavior to Porfiry.
Raskolnikov attends the Marmeladovs' post-funeral banquet at Katerina Ivanovna's apartment. The atmosphere deteriorates as guests become drunk and the half-mad Katerina Ivanovna engages in a verbal attack on her German landlady. With chaos descending, everyone is surprised by the sudden and portentous appearance of Luzhin. He sternly announces that a 100 ruble banknote disappeared from his apartment at the precise time that he was being visited by Sonya, whom he had invited in order to make a small donation. Sonya fearfully denies stealing the money, but Luzhin persists in his accusation and demands that someone search her. Outraged, Katerina Ivanovna abuses Luzhin and sets about emptying Sonya's pockets to prove her innocence, but a folded 100 ruble note does indeed fly out of one of the pockets. The mood in the room turns against Sonya, Luzhin chastises her, and the landlady orders the family out. But Luzhin's roommate Lebezyatnikov angrily asserts that he saw Luzhin surreptitiously slip the money into Sonya's pocket as she left, although he had thought at the time that it was a noble act of anonymous charity. Raskolnikov backs Lebezyatnikov by confidently identifying Luzhin's motive: a desire to avenge himself on Raskolnikov by defaming Sonya, in hopes of causing a rift with his family. Luzhin is discredited, but Sonya is traumatized, and she runs out of the apartment. Raskolnikov follows her.
Back at her room, Raskolnikov draws Sonya's attention to the ease with which Luzhin could have ruined her, and consequently the children as well. But it is only a prelude to his confession that he is the murderer of the old woman and Lizaveta. Painfully, he tries to explain his abstract motives for the crime to the uncomprehending Sonya. She is horrified, not just at the crime, but at his own self-torture, and tells him that he must hand himself in to the police. Lebezyatnikov appears and tells them that the landlady has kicked Katerina Ivanovna out of the apartment and that she has gone mad. They find Katerina Ivanovna surrounded by people in the street, completely insane, trying to force the terrified children to perform for money, and near death from her illness. They manage to get her back to Sonya's room, where, distraught and raving, she dies. To Raskolnikov's surprise, Svidrigailov suddenly appears and informs him that he will be using the ten thousand rubles intended for Dunya to make the funeral arrangements and to place the children in good orphanages. When Raskolnikov asks him what his motives are, he laughingly replies with direct quotations of Raskolnikov's own words, spoken when he was trying to explain his justifications for the murder to Sonya. Svidrigailov has been residing next door to Sonya, and overheard every word of the confession.
Razumikhin tells Raskolnikov that Dunya has become troubled and distant after receiving a letter from someone. He also mentions, to Raskolnikov's astonishment, that Porfiry no longer suspects him of the murders. As Raskolnikov is about to set off in search of Svidrigailov, Porfiry himself appears and politely requests a brief chat. He sincerely apologises for his previous behavior and seeks to explain the reasons behind it. Strangely, Raskolnikov begins to feel alarmed at the thought that Porfiry might think he is innocent. But Porfiry's changed attitude is motivated by genuine respect for Raskolnikov, not by any thought of his innocence, and he concludes by expressing his absolute certainty that Raskolnikov is indeed the murderer. He claims that he will be arresting him soon, but urges him to confess to make it easier on himself. Raskolnikov chooses to continue the struggle.
Raskolnikov finds Svidrigailov at an inn and warns him against approaching Dunya. Svidrigailov, who has in fact arranged to meet Dunya, threatens him with the police, but Raskolnikov is unconcerned and follows him home. When Raskolnikov finally departs, Dunya, who has been watching them, approaches Svidrigailov and demands to know what he meant in his letter about her brother's 'secret'. She reluctantly accompanies him to his rooms, where he reveals what he overheard and attempts to use it to make her yield to his desire. Dunya, however, has a gun and she fires at him, narrowly missing: Svidrigailov gently encourages her to reload and try again. Eventually she throws the gun aside, but Svidrigailov, crushed by her hatred for him, tells her to leave. Later that evening he goes to Sonya to discuss the arrangements for Katerina Ivanovna's children. He gives her 3000 rubles, telling her she will need it if she wishes to follow Raskolnikov to Siberia. He spends the night in a miserable hotel and the following morning commits suicide in a public place.
Raskolnikov says a painful goodbye to his mother, without telling her the truth. Dunya is waiting for him at his room, and he tells her that he will be going to the police to confess to the murders. He stops at Sonya's place on the way and she gives him a crucifix. At the bureau he learns of Svidrigailov's suicide, and almost changes his mind, even leaving the building. But he sees Sonya, who has followed him, looking at him in despair, and he returns to make a full and frank confession that he is the murderer.
Due to the fullness of his confession at a time when another man had already confessed Raskolnikov is sentenced to only eight years of penal servitude. Dunya and Razumikhin marry and plan to move to Siberia, but Raskolnikov's mother falls ill and dies. Sonya follows Raskolnikov to Siberia, but he is initially hostile towards her as he is still struggling to acknowledge any moral culpability for his crime, feeling himself to be guilty only of weakness. It is only after some time in prison that his redemption and moral regeneration begin under Sonya's loving influence.