Ellen Morris believes there is someone or something trying to get her. Her husband and psychotherapists believe she's a paranoid schizophrenic. On their way to the mental institution, the Morris' car breaks down. When her husband goes to get help, Ellen stays in the car and is attacked by her mysterious assailant, The Nightmare Man. Escaping for her life into some nearby woods, Ellen stumbles upon a country house where two young couples are spending the weekend. Now, everyone is in danger. But is the killer real or is it only in Ellen's mind. Is he outside or already someone we know inside the house? As people start dying, nobody knows who they can trust or who is the real Nightmare Man!