Will Ferrell plays Harold Crick, a I.R.S. Agent leading a monotonous, routinized and solitary life. He suffers from O.C.D, has few friends, dislikes his job and highly depends on his wristwatch. One day everything changes, after he starts hearing a voice of an English woman narrating everything that happens to him, from the things he does to his innermost thoughts and feelings. He decides to ignore the voice, but then hears that an event could lead to his death and becomes worried. He turns to literary expert Jules Hilbert for help.