Meursault, the narrator, is a young man living in Algiers. After receiving a telegram informing him of his mother’s death, he takes a bus to Marengo, where his mother had been living in an old persons’ home. He sleeps for almost the entire trip. When he arrives, he speaks to the director of the home. The director allows Meursault to see his mother, but Meursault finds that her body has already been sealed in the coffin. He declines the caretaker’s offer to open the coffin.
That night, Meursault keeps vigil over his mother’s body. Much to his displeasure, the talkative caretaker stays with him the whole time. Meursault smokes a cigarette, drinks coffee, and dozes off. The next morning, before the funeral, he meets with the director again. The director informs him that Thomas Perez, an old man who had grown very close to Meursault’s mother, will be attending the funeral service. The funeral procession heads for the small local village, but Perez has difficulty keeping up and eventually faints from the heat. Meursault reports that he remembers little of the funeral. That night, he happily arrives back in Algiers.
The next day, Meursault goes to the public beach for a swim. There, he runs into Marie Cardona, his former co-worker. The two make a date to see a comedy at the movie theater that evening. After the movie they spend the night together. When Meursault wakes up, Marie is gone. He stays in bed until noon and then sits on his balcony until evening, watching the people pass on the street.
The following day, Monday, Meursault returns to work. He has lunch with his friend Emmanuel and then works all afternoon. While walking upstairs to his apartment that night, Meursault runs into Salamano, an old man who lives in his building and owns a mangy dog. Meursault also runs into his neighbor, Raymond Sintes, who is widely rumored to be a pimp. Raymond invites Meursault over for dinner. Over the meal, Raymond recounts how he beat up his mistress after he discovered that she had been cheating on him. As a result, he got into a fight with her brother. Raymond now wants to torment his mistress even more, but he needs Meursault to write a letter to lure his mistress back to him. Meursault agrees and writes the letter that night.
The following Saturday, Marie visits Meursault at his apartment. She asks Meursault if he loves her, and he replies that “it didn’t mean anything,” but probably not. The two then hear shouting coming from Raymond’s apartment. They go out into the hall and watch as a policeman arrives. The policeman slaps Raymond and says that he will be summoned to the police station for beating up his mistress. Later, Raymond asks Meursault to testify on his behalf, and Meursault agrees. That night, Raymond runs into Salamano, who laments that his dog has run away.
Marie asks Meursault if he wants to marry her. He replies indifferently but says that they can get married if she wants to, so they become engaged. The following Sunday, Meursault, Marie, and Raymond go to a beach house owned by Masson, one of Raymond’s friends. They swim happily in the ocean and then have lunch. That afternoon, Masson, Raymond, and Meursault run into two Arabs on the beach, one of whom is the brother of Raymond’s mistress. A fight breaks out and Raymond is stabbed. After tending to his wounds, Raymond returns to the beach with Meursault. They find the Arabs at a spring. Raymond considers shooting them with his gun, but Meursault talks him out of it and takes the gun away. Later, however, Meursault returns to the spring to cool off, and, for no apparent reason, he shoots Raymond’s mistress’s brother.
Meursault is arrested and thrown into jail. His lawyer seems disgusted at Meursault’s lack of remorse over his crime, and, in particular, at Meursault’s lack of grief at his mother’s funeral. Later, Meursault meets with the examining magistrate, who cannot understand Meursault’s actions. The magistrate brandishes a crucifix and demands that Meursault put his faith in God. Meursault refuses, insisting that he does not believe in God. The magistrate cannot accept Meursault’s lack of belief, and eventually dubs him “Monsieur Antichrist.”
One day, Marie visits Meursault in prison. She forces herself to smile during the visit, and she expresses hope that Meursault will be acquitted and that they will get married. As he awaits his trial, Meursault slowly adapts to prison life. His isolation from nature, women, and cigarettes torments him at first, but he eventually adjusts to living without them, and soon does not even notice their absence. He manages to keep his mind occupied, and he sleeps for most of each day.
Meursault is taken to the courthouse early on the morning of his trial. Spectators and members of the press fill the courtroom. The subject of the trial quickly shifts away from the murder to a general discussion of Meursault’s character, and of his reaction to his mother’s death in particular. The director and several other people who attended the vigil and the funeral are called to testify, and they all attest to Meursault’s lack of grief or tears. Marie reluctantly testifies that the day after his mother’s funeral she and Meursault went on a date and saw a comedic movie. During his summation the following day, the prosecutor calls Meursault a monster and says that his lack of moral feeling threatens all of society. Meursault is found guilty and is sentenced to death by beheading.
Meursault returns to prison to await his execution. He struggles to come to terms with his situation, and he has trouble accepting the certainty and inevitability of his fate. He imagines escaping and he dreams of filing a successful legal appeal. One day, the chaplain comes to visit against Meursault’s wishes. He urges Meursault to renounce his atheism and turn to God, but Meursault refuses. Like the magistrate, the chaplain cannot believe that Meursault does not long for faith and the afterlife. Meursault suddenly becomes enraged, grabs the chaplain, and begins shouting at him. He declares that he is correct in believing in a meaningless, purely physical world. For the first time, Meursault truly embraces the idea that human existence holds no greater meaning. He abandons all hope for the future and accepts the “gentle indifference of the world.” This acceptance makes Meursault feel happy.