Marnie Watson (Famke Janssen) is released from prison under house arrest after murdering her violent husband in a fatal act of self-defence. The conditions of her release state she must wear an electronic ankle bracelet and remain within one hundred feet of her home but there's something malevolent lurking in the shadows. Having thought her nightmare was finally over, Marnie discovers that it's only just begun as she realises her husband is just as evil in death as he was in life.