Beau (Joaquin Phoenix) is a neurotic and paranoid man who inherited mental illness from his father. He's in therapy for his problems, but has scheduled a flight home to visit his mother Mona (Patti LuPone).

On the morning of the day he's scheduled to get on a flight, he wakes to hear that she has been killed in a car accident. Beau then embarks on an journey to get home in order to attend Mona's funeral, but the trip is difficult as he suffers from hallucinations and doesn't know which of the horrors he faces is real.