In The Boogeyman, high schooler Sadie Harper and her younger sister Sawyer are still reeling from the loss of their mother. Their father, Will, a therapist, is stuck in his own grief and unable to give them the support or comfort they need. When a new patient shows up at their home desperate for help, he brings a demonic entity with him. This terrifying entity latches onto the Harper family and begins spreading fear and turmoil through the home as it feeds off their suffering.