Trevor Reznik (Christian Bale) hasn't slept in a year. The shocking deterioration in his mental health has made his every waking moment an unrelenting state of confusion, paranoia, guilt, terror and anxiety. His only solace comes from an affectionate prostitute (Jennifer Jason Leigh). When cryptic notes turn up in his apartment and when hallucinations of a co-worker that no-one else sees cause a gruesome machine shop injury, he embarks on a journey to find out whether there is an elaborate plot to drive him mad, or his fatigue has simply robbed him of reason. The more he learns, the less he wants to know.