Three years after the events of the previous film, the protagonist is found living in a psychiatric facility, still haunted by her past encounters with her brother, a masked killer. Despite having seemingly defeated him in their last confrontation, she is consumed by fear and paranoia that he may return. Her fears are proven justified when he tracks her down to the facility in pursuit of finishing what he began. Their reunion is a tense and harrowing encounter that draws a line under their long-standing familial conflict.

Meanwhile, a group of enterprising college students is chosen to spend the night in the killer's childhood home for a live-streamed internet show on Halloween night. The event, orchestrated by a reality TV entrepreneur, aims to exploit the macabre history of the house and the urban legends surrounding the previous murders. The students, armed with head-mounted cameras and a variety of surveillance equipment, begin to explore the decrepit house. They quickly realize the show's ratings are the least of their worries as they encounter more than they bargained for within the supposedly empty walls.