A young urban professional who works for a major car manufacturer can't sleep. Although he doesn't have any of the associated afflictions, he stumbles across support groups as a means to let out whatever emotions he is feeling, which in turn allows him to sleep. But the use of these support groups is ruined when he meets a young woman named Marla Singer, who is also going to all these support group meetings. Because he knows she too is not afflicted with any of the maladies for which the groups exist, her presence has lessened the impact of the stories he hears. His life changes when he meets a soap manufacturer named Tyler Durden, who in many ways is the antithesis of the insomniac. Due to unusual circumstances with his own condo, the insomniac moves in with Tyler, who lives in a large dilapidated house in an otherwise abandoned part of town. After a bit of spontaneous roughhousing with Tyler in a bar parking lot, the insomniac finds it becomes a ritual between the two of them, which helps him cope with the other more difficult aspects of his life. The fights also attract a following, others who not only want to watch but join in. Understanding that there are other men like them, the insomniac and Tyler begin a secret fight club. As the fight club's popularity grows, so does its scope in all aspects. Marla becomes a circle not specifically of the fight clubs but of Tyler and the insomniac's collectives lives. As the nature of the fight clubs becomes out of control in the insomniac's view, the insomniac's life, in association, is one where he no longer understands what is happening around him, or how he can get out of it without harming himself.