Trevor Reznik (Christian Bale) is a machinist whose insomnia has led to him becoming emaciated. His appearance and behavior keep his coworkers away, and they eventually turn against him when he is involved in an accident, which causes his coworker, Miller, to lose his left arm. Trevor, who was distracted by an unfamiliar coworker named Ivan, is blamed for the accident. No one at the factory knows of Ivan and there are no records of him. Trevor seems to find comfort in the arms of Stevie, a sex worker with genuine affection for him, and with Maria, a waitress at an airport diner he frequents. He is haunted by brief flashes of recurring imagery, and things such as his car cigarette lighter take on a menacing air. A mysterious series of post-it notes appear on his refrigerator, depicting a game of hangman.