Sadie Harper, a young high school student, and her little sister Sawyer are still reeling from the recent death of their mother. Devastated by his own pain, their father Will, a therapist by profession, gives them neither the support nor the affection that they try to claim from him. When a desperate patient shows up unexpectedly at their home asking for help, they bring in a terrifying entity that preys on the families and feeds on their greatest suffering.