Fight Club is a provocative and darkly satirical film directed by David Fincher, based on the novel by Chuck Palahniuk. It's a critique of consumerism, modern masculinity, and societal alienation.
The story is narrated by an unnamed, insomniac office worker (Edward Norton) who is deeply dissatisfied with his mundane, materialistic life. He finds temporary relief from his chronic insomnia by attending various support groups for illnesses he doesn't have, finding catharsis in the shared suffering of others.
His fragile peace is disrupted by the arrival of Marla Singer (Helena Bonham Carter), another "tourist" who exposes his fraudulent behavior and makes him feel like his emotional outlets are no longer effective. His insomnia returns.
On a business trip, he encounters Tyler Durden (Brad Pitt), a charismatic, anarchistic soap salesman. Tyler embodies everything the Narrator isn't: confident, rebellious, and completely unburdened by societal norms. After the Narrator's apartment is mysteriously destroyed in an explosion, he calls Tyler, and they meet at a bar. Tyler challenges the Narrator to hit him, and their impromptu street fight ignites a strange sense of liberation and vitality for both of them.
This leads to the formation of Fight Club, an underground bare-knuckle boxing club held in the basement of a bar. It attracts other disaffected men seeking an escape from their emasculating lives and a primal connection. The rules of Fight Club are famously strict, the first two being: "You do not talk about Fight Club."
As Fight Club gains popularity and expands, Tyler's influence grows. He transforms the simple fighting into "Project Mayhem," a much more radical and destructive anti-consumerist, anti-establishment organization. Project Mayhem embarks on increasingly dangerous acts of vandalism, sabotage, and even terrorism, all aimed at dismantling modern society's structures and values.
The Narrator becomes increasingly disturbed by Tyler's escalating extremism and cult-like control over the members of Project Mayhem. He also finds himself caught in a bizarre love triangle with Tyler and Marla, who have an intense and volatile sexual relationship that the Narrator is both jealous of and disgusted by.
As the Narrator tries to understand Tyler's ultimate plan and stop Project Mayhem, he uncovers a shocking truth: Tyler Durden is not a separate person, but an alter ego, a dissociative personality within the Narrator's own mind. All the interactions he's had with Tyler were self-inflicted, and he himself is the mastermind behind Fight Club and Project Mayhem.
The climax sees the Narrator desperately trying to prevent Project Mayhem from carrying out its final, devastating act: blowing up several credit card company buildings to erase all debt. He confronts Tyler, who tries to stop him. In a final, desperate act to "kill" Tyler and regain control of his mind, the Narrator shoots himself in the mouth, seemingly destroying the Tyler persona.
The film ends with the Narrator, now seemingly free from Tyler's influence, holding hands with Marla as they watch the city's financial buildings explode, leaving the audience to ponder the implications of his actions and the film's complex message about rebellion, identity, and the destructive nature of unchecked ideologies.