A woman with a shady past, Ruby Claire (Piper Laurie) is the single mother of Leslie (Janit Baldwin), a teenager who is deaf and mute. Ruby operates a drive-in movie theater and employs a number of ex-criminals, some of who start to die in bizarre ways. Eventually, Ruby discovers that the spirit of her dead mobster husband has possessed Leslie and is seeking revenge through the tormented girl. As Leslie picks off her dad's former associates, she also begins to target Ruby herself.