Warning: Huge, horrifying spoilers for Hereditary below!
Hear ye, hear ye! It's time to spoil the biggest horror movie of 2018! Yep, we're talking about Hereditary, the super f*cked-up feature that scared the living daylights out of everyone at Sundance. We've already broken down just how scary the film is, so hopefully you know whether or not you're going to see it. In the meantime, we're breaking down the biggest twist in the film. So, if you decided to sit this one out but you're morbidly curious, or if you simply love reading spoilers, here's a very basic rundown of what goes down.
OK, before we get deep into spoiler territory, allow me to catch you up on the early parts of the film. At the very beginning, the matriarch of the Graham family dies. We open on the funeral sequence: the mother of the household, Annie (Toni Collette), seems to be pretty numbed by her mother's death. She lives with her husband, Steve (Gabriel Byrne), and her son and daughter, Peter (Alex Wolff) and Charlie (Milly Shapiro). While Grandma's death is the launching point of the film, the real action begins when we hit another unspeakable tragedy.
Shortly after Grandma's death, Peter decides to go to a party at his friend's place. Annie, noticing that Charlie has really withdrawn into herself since her grandmother's death, forces Peter to bring his sister along. At the party, Charlie accidentally eats a piece of cake that's filled with nuts (which she is allergic to). Don't ask me what a nutty cake is doing at a party — I don't know about teenagers these days. Charlie has a severe allergic reaction and her throat starts to close up. Peter frantically speeds to the hospital, trying to get her there in time. He swerves to avoid hitting some roadkill, right as Charlie sticks her head out the car window, trying to catch her breath. In some kind of freak accident, Peter's swerve perfectly aligns with a telephone pole, and Charlie is beheaded and killed instantly.
Still with me? I know. It's a lot.
Annie completely falls apart, and the rest of the family aren't in great shape either. At this point, the whole family begins experiencing strange apparitions. Annie thinks she sees her mother in the shadows of the house. Peter thinks he hears his sister. It's all very strange. Through a grief support group, Annie meets an old friend of her mother's named Joan (Ann Dowd). Joan has also lost a loved one.
Some time passes. Joan runs into Annie and tells her of a miraculous experience: she's met with a psychic medium, and she's managed to communicate with the spirit of her dead grandchild! Annie seems completely incredulous, but is flabbergasted when Joan shows her firsthand. Joan gives Annie the special ghost candle and an incantation that will allow her to communicate with Charlie.
Annie tries the ritual for herself, and what do you know, she manages to communicate with Charlie. But as soon as she contacts the spirit, Charlie seems to be angry and malevolent. She begins to terrorize the family with horrifying nightmares and hauntings. Slowly, she drives her brother Peter insane. Annie goes to talk to Joan but can't seem to find her. That's when everything starts to reveal itself: Joan isn't home, but we see a big picture of Peter on her kitchen table, surrounded by candles. This isn't a story of spiritual connection and healing! This is some crazy demonic possession sh*t!
Annie knows something is up. She decides to root around in her mother's old things and discovers a book that mentions a figure called King Paimon. Apparently he's a demon who serves Lucifer, and he likes to have a male body as his human host. A lot of things click into place here: that spirit terrorizing the family wasn't Charlie's at all; it was the demonic entity, King Paimon, who's set his sights on claiming Peter's body. At the same time, Annie also discovers that the headless, rotting dead body of her mother is casually hanging out in the attic. Cool.
The Finale and the Aftermath
So, basically, everything devolves into chaos. Annie and Steve pull Peter out of school because he slams his face into a desk (because Paimon is terrorizing him). At home, Annie tries to convince her husband that Peter is in danger and that a lot of bad sh*t is about to happen. Steve thinks Annie has gone off the deep-end, and he doesn't believe a word she says. In order to ward off Paimon, she throws Charlie's old sketch book into the fireplace (it was the physical object she used in her ritual to contact her daughter beyond the grave). Then, for some inexplicable reason, Steve bursts into flames and dies.
In the final sequence, Annie gets possessed by Paimon. Peter wakes up and wanders around the house, and Annie literally crawls along the walls, stalking him. When he finally notices her, he flips out and runs up to the attic. His mother chases after him and starts viciously banging her head on the trapdoor in the ceiling over and over again when he escapes her clutches. (Yep, you read that correctly.)
Peter quickly realizes that the attic is filled with (naked) followers of Grandma's cult, who start to close in on him. Annie then seems to float into the attic, somehow, where she proceeds to saw off her own head with what appears to be a garrote wire. Peter loses it, and seeing no other option, jumps out the attic's glass window and appears to die (or at least lose consciousness) on the ground below. The worshipers drag his body up into Charlie's old tree house and complete the ritual. In the final sequence, Peter's body wakes up, and Joan breaks everything down for him.
Basically, the whole movie has been an attempt to summon King Paimon and put him in a human host. That human host is Peter. From context clues, it seems Charlie was supposed to be the original vessel, but Paimon did not like her female form. Thus, they needed to "correct" Paimon's desired body, and so we land on Peter. The previous ritual, performed by Annie, was to welcome Paimon into the Graham household and to make Peter available as the vessel. Peter looks around the tree house, which is filled with worshipers who bow at his feet. Joan places a crown on his head, and we cut to black.