The Stranger follows Meursault, an emotionally detached man living in Algeria who experiences life without attaching deeper meaning to events. When his mother dies, he shows no grief, focusing instead on physical sensations like heat and light. This lack of expected emotion sets him apart from society.

Soon after, Meursault becomes involved in a series of ordinary events—beginning a relationship with Marie and helping his neighbor Raymond—until a confrontation on a beach leads him to impulsively shoot and kill a man. The act seems less driven by intention than by the overwhelming heat and momentary disorientation.

During his trial, the court focuses less on the murder itself and more on Meursault's character, especially his indifference at his mother's funeral. He is judged not only as a criminal but as a moral outsider who fails to conform to social expectations of emotion and behavior. He is ultimately sentenced to death.

While awaiting execution, Meursault comes to accept the absurdity of life—the idea that the universe has no inherent meaning and that death is inevitable. Rejecting religion and false hope, he finds peace in embracing life as it is, without illusion.

The novel explores themes of existentialism, absurdity, alienation, and authenticity, questioning whether meaning is discovered or created, and whether society punishes those who refuse to conform to its expectations.