Historian Doris Kearns Goodwin explains the history of the Roanoke house ("Big Shaker Mansion"), built in 1792 by Edward Philippe Mott, to the documentary filmmakers.
In the dramatic reenactment, we see Edward, a rich nobleman and art collector, buy up an entire collection. Edward had severe social anxiety. He left Philadelphia's busy atmosphere to build a reclusive sanctuary in North Caroline -- the Roanoke house. He lived there with his male lover/slave and his extensive art collection. Soon into arriving on the property, they are plagued by bad tidings and accidents.
Eventually, his prized art, including his precious Peale, is destroyed in the middle of the night. Edward is distressed and furiously questions the servants, abusing them. One of the servants reports seeing "a big white woman and a young man" (the Butcher and her son) before she heard Edward scream. He locks the servants (all except for Guinness) in the cellar, until the "murderer" of the painting confesses.
Guinness is displeased with Edward's actions. Edward insults him and tells him to stay away from him, in a rage. He sees the blood moon rise. That night, as was reported by Guinness, Edward was captured by the Butcher and her crew, speared and burned alive. Guinness rode off, told his tale, but was accused of Edward's murder and thrown in jail. He failed to tell anyone about the servants, who all starved to death. The house remained in the Mott family trust for years, until the last Mott (Dandy) died in 1952. At that point, other owners purchased the house.
In the "present day" dramatic reenactment, Matt calls the cops asking for assistance with the mob outside their house. Ambrose threatens them with a "merciless reckoning." Matt instructs Shelby to take Flora and make a run for the truck while he distracts the colonists. On their way out of the house, a twisted Asian ghost crab-walking backwards snatches Flora and carries her through the house, with Matt and Shelby giving chase. The Roanoke colonists set fire to their cars outside.
The ghost leaves Flora, and they release that all of the past victims of the Butcher have cornered and corralled them into a section of the house where the colonists are attempting to break in. Shelby, Matt and Flora run into the basement, where they encounter Edward's ghost. He convinces them to follow him through his underground tunnels, where he will help them escape the Butcher because he doesn't want any more Butcher's victims intruding on his solitude.
He leads them into the woods, then disappears. As they wander, they're captured by the Polk family, who take them back to their barn. It's revealed that the Polks are cannibals and they kept Elias alive in order to eat him. Since his "meat" has gone rancid, they brutally kill him. Mama Polk reveals that her kin made a deal with the Butcher many years ago -- they remained unharmed so long as the Butcher was able to consecrate her land. Mama intends to return the Millers to the Butcher, especially since the Millers got their "babies" (the two feral boys) taken away.
At the police station, Lee is questioned for 48 hours about Mason's death. Eventually, they release her because they can't find any inconsistencies in her story. She sees texts from Matt on her phone letting her know that Flora is safe.
The Polks drive the Miller family back to the Butcher. On the way, Matt wrestles the gun from one of them, shooting and killing the Polk brother driving. They run for it into the woods and hide. The Polks find them easily and hold them at gunpoint.
At the police station, Lee asks the policeman for a ride back to the house, after Matt ignores her call.
Mama Polk axes Shelby's ankle, incapacitating her, after putting Flora back in the truck, so that they can no longer run. As they're lying in the truck being driven to the Butcher, Shelby tries to convince Matt to save Flora but Matt is convinced that they're goners.
At the house, the family is delivered to the Butcher. Lee drives up, but the policeman abandons her there, driving away. As the Butcher prepares to kill Flora first, Ambrose intervenes, attacking his mother and tumbling them both into the fire. Edward releases Shelby and Matt from their restraints. In the fracas, the Pig Man moves to finish off Flora, but Lee arrives driving the car and hits him. The family drives away as the Butcher's flaming figure chases after them.
They stay in a cheap motel until Shelby's sister is able to send them enough money to fly back to LA. Shelby goes to take a shower and is attacked by the Butcher -- but it turns out to just be a recurring nightmare that she repeatedly has. She notes that she's not sure she'll ever get over the events they experienced.