A young girl in a yellow dress stands outside of a seemingly-abandoned Victorian home in Los Angeles. Bone wood chimes hang from a tree. Twin brothers Troy and Bryan throw a rock through the window and prepare to go inside, carrying bats. The girl tells them that they're going to die in there, but they ignore her and go in while she says repeatedly that they'll regret it.
Inside, the twins start destroying the furnishings. They find a dead possum and admire it as fresh blood oozes from it. A nearby door closes, seemingly on its own, and the brothers dare each other into investigating. The door leads to the cellar and they hear a popping noise. On the shelves and tables they find jars containing severed body parts from babies. As they look around and Troy complains about the stink, a figure moves in the shadows behind them. Bryan insists on leaving and goes up the stairs, and the popping noise stops. He turns around calls to his brother, who has disappeared. Finally he goes downstairs to find Troy and locates his brother... his throat cut. A bald figure in a white robe charges at Bryan as he turns around and screams. Outside, the girl watches the house.
Vivien Harmon meets with her gynecologist and he tells her that there are preemptive hormone treatments for they can give her. He assures him that they have no side effects and Vivien says that she's trying to get control of her body after what happened. When she refuses, the doctor asks what she's afraid of and gives her the prescription.
Vivien returns home and hears someone moving upstairs. She calls 911 to report an intruder and they say they'll send a police car. Vivien then grabs a knife and goes up the stairs, and discovers her husband Ben with another woman. He races after her and apologizes and she slashes him with the knife before walking away.
Sometime later, Ben, Vivien, their daughter Violet, and the family dog Hallie are driving to Los Angeles. Ben tries to take Vivien's hand but she refuses. They arrive at their new home and the realtor, Marcy, greets them. She brings them in and explains that the house was built in the 1920s by a doctor to a star, and the most recent owners, a gay couple, restored it. Ben says that he's a psychiatrist and asks about where he can set up a home office so he can spend more time with his family. Hallie barks at the basement door and Violet goes to investigate. She gets the door open and goes downstairs. Seeing nothing, she goes back upstairs... unaware that something or someone is watching her from the grill.
As they look over the house, Ben notes that Vivien is a retired cellist. When Marcy asks why she quit, Vivien avoids the question and comments on a mural beneath the wallpaper. The realtor says that the last owners covered it up. In the interests of full disclosure, she tells the Harmons that the last couple died in a murder-suicide and she sold the house to them. Ben figures that why they got the house for half the going price and Marcy admits that everything else she has available is much more expensive. Violet asks where the deaths occurred, and when Marcy confirms they happened in the basement, Violet says that they'll take the house.
The Harmons begin moving their furniture in and Ben suggests they go to bed. Vivien worries that Violet will have trouble fitting in, and points out that the house is creepy. Ben insists that the value of the house makes up for it and begins stroking her, insisting that they deserve some good after everything they've gone through. Vivien pulls away and says there is some stuff in the kitchen that she has to unpack. As she goes, she thanks Ben for trying and says that she's trying as well, but warns that it will take some time.
Violet arrives for her first day at school, smoking, and three of the cool girls, led by Leah, confront her about it. She apologizes and stomps it out, and Leah complains about her littering. She threatens to make Violet eat the cigarette or beat her up, and another girl, Becca, explains that Leah's mother died of lung cancer. Leah grabs her and Violet spits in her face, breaks away, and runs off.
Vivien works on the wallpaper and removes it, revealing the mural beneath. Adelaide, the girl from 1978, comes in behind her and tells her that Vivien's going to die in the house. Vivien demands to know why Adelaide is there and an older woman, Constance, comes in. She sends Adelaide home and explains that she's the Harmons' next-door neighbor. Once Adelaide leaves, Constance complains that she's a monster because she's developmentally-challenged and tells Vivien that her back door was open. She warns that Adelaide has issues with the house and explains that she runs a dog kennel from her home, and admires Vivien's diamond earrings. Constance talks about how she used to have diamond earrings when she was younger when she came to Los Angeles to become an actress. When that fell through, she gave birth to Adelaide and couldn't work. Vivien tries to get her out and Constance prepares to leave. First she gives Vivien a housewarming gift: a case. As she goes, she says that she's glad Vivien is getting rid of the wallpaper. Vivien opens the case and finds a bundle of sage, and Constance explains that it's for cleaning the spirits of the house.
That night, Vivien lights the sage and carries it through the house. She hears the wind whistling up in the attic and goes to investigate, manages to turn on the light, and is frightened by a rubber full-body fetish suit hanging from the ceiling. Vivien screams and Ben and Violet come to investigate As they go back downstairs, Ben looks admiringly at the suit but then takes it to the garbage and throw sit away.
Later, Ben meets at his home office with his first patient, Tate Langdon. Tate talks of how he's preparing for the noble war, and that he's ready to kill people he likes. He insists that it's a filthy world that they live in and that he's helping people by killing them and taking them somewhere clean and kind. Tate talks about how Indians believed that cutting themselves would release the evil spirits, and briefly imagines himself bleeding and bloody. He calls his mother a cocksucker and explains that his father left because of that.
Violet is in the bathroom cutting herself on the arm. Tate comes in behind her and says that if she wants to cut herself, she should do it vertically. When she asks how he got in, Tate points out that she should lock the door and walks away.
That night, Ben hears voices and gets out of bed. He goes to the downstairs fireplace and lights it. When Vivien comes down and asks what he's doing, Ben wonders if he's on an acid trip.
The next day, Vivien is drying her sheets in the yard when Moira O'Hare, the housekeeper, walks up. Vivien admits she didn't know that the house had a housekeeper. Moira gives her schedule and explains it was the deal with the last owners, and Vivien says that she's not sure they need a housekeeper. The housekeeper says that the house has feelings and that if she'll mistreat it, Vivien will regret it. She asks to come inside to call a cab and as she waits, explains that she's the one who found the bodies of the previous owners and that the two men fought a lot. Ben comes into the kitchen and Vivien introduces her. Ben sees her as a young woman. Moira leaves to get her coat and Ben admits that he's surprised that Vivien wants to hire her. Vivien tells Moira that she's hired and after the woman leaves, Ben admits that Vivien is always surprising him. He tries to kiss her but she backs away. He says that she'll have to forgive him one day and leaves.
Ben meets with his Tate again, who complains about light sensitivity from his medication. He talks about lying and Tate asks him if he thinks that he's lying. Ben points out that light sensitivity isn't a side effect, and says that he has to call the police if he thinks Tate is a danger to his fellow students. However, Ben says that he hasn't called the police yet and insists that everyone can get better. Tate says that he didn't take the meds because he was afraid they'd make him impotent, and that he's met someone.
Later, Tate and Violet meet in her bedroom and compare their cuts and why they inflicted them. Violet admits that she hates her new school and Tate asks why they moved there. She explains that Vivien had a miscarriage and then six months later caught Ben having affair. Ben finds them together and tells Tate to leave. Once he leaves, Ben tells Violet to stay away from the boy. Tate storms down the stairs, pounding on the balustrade.
Ben finishes shaving and hears Hallie barking. He goes into the next room and finds the young Moira masturbating on the couch. He goes to the bathroom and does the same, sobbing, and then hears a man in the yard call out that his family is in danger. Ben looks down and sees the man, his face and hands hideously burned, standing between Vivien's hanging sheets. He runs down but finds no one.
Vivien returns home with groceries and hears a noise behind her. When she turns, she finds the refrigerator and cupboard doors open and Adelaide, giggling at her. As Vivien demands to know why Adelaide is in her house, she's unaware that the ghosts of the twins are behind her.
Once Constance arrives to get her daughter, Vivien and Ben meet with her and tell Adelaide to stay outside. She claims that the twins did it and giggles. She finally agrees not to come there again when Vivien grabs her by the face. As they go, Hallie bites Adelaide and the girl says she shouldn't have done that. As Constance goes, she briefly turns vicious and tells Vivien that if she touches Adelaide again, she'll break Vivien's arm.
Ben tries to report Tate to the authorities and is put on hold. As he waits, the young Moira comes in and asks to clean in his office. She comes in anyway, insisting that she has to do it. She then unbuttons her blouse and invites him to touch her, and Ben tells her to get out. Moira says that Vivien isn't home and promises not to tell, and tells him to do again what he did the other day. Violet comes in and is shocked to see the old Moira coming on to her father. She runs off and Ben starts to go after her, but gives up.
At school, Leah and her friends Abby and Becca beat up Violet in the cafeteria when she lights up another cigarette. Violet finally burns Leah with the cigarette to get away.
Vivien removes the rest of the wallpaper from the mural. Ben sees it and says that whoever did it had some deep issues. Vivien says that she finds it comforting and he comments that he finds her most attractive when she's sweaty and without makeup. He tries to kiss her again but Vivien tells him no and pushes him away. Ben demands to know how long she's going to refuse to forgive him and Vivien says that it's not about the sex, and that she can't bear to look at his face without remembering it when she caught him in bed with one of his students. She reminds him of the miscarriage and her pain, and Ben reminds her that his son died. Vivien doesn't buy his emotional outbursts during therapy and tells him to say how he really feels. Ben complains that she got a dog instead of turning to him and they haven't had sex in over a year. He insists that he loves her and the only thing he's scared of is losing his family, and now they have a second chance. Ben asks if she wants it as well and tries to embrace her, but she starts shoving him. He grabs her and they kiss, falling down on the sofa to make love. Afterward, Ben says that they're going to be happy there.
That night, Violet returns home and Vivien sees her bruises from the fight at school. Her daughter claims that she fells down but Vivien doesn't buy it and hopes that they look worse than Violet does. Vivien suggests they put her in a different school but Violet says that she's not afraid. She apologizes to Violet about overlooking her and insists that she and Ben still love each other. Violet says that Ben is a shithead and Vivien admits that he was, but that they have history together and they need each other. She asks what scares her mother and Vivien says that lately, everything scares her.
Violet talks to Tate and vows to kill Leah. He says that if she won't kill Leah then she needs to scare her. He suggests that Violet tell her that she's a coke dealer and invite the girl to the house for a free sample, and then he'll terrify her.
Vivien is in her room putting lotion on her legs when a man in the rubber suit enters. She assumes that it's Ben and gives him points for creativity, and offers to go for round two.
In the kitchen, Ben is back in a trance. He lights the gas stove and extends his hands toward the flames.
The rubber man takes Vivien in the bedroom. As they make love, she has visions of the mural.
Constance stops Ben from burning his hand and tells him that it isn't his time yet. She says that he should enjoy the house and go back to bed. He goes to the bedroom and gets into bed next to Vivien, who says that she loves him. He mindlessly tells her that he loves her as well.
The next day, Leah comes to the house and Violet takes her down to the basement to get her drugs. She directs Leah into the next room and turns on the lights, revealing Tate. He calls Leah a coke whore and tells Violet to turn off the lights. He laughs hysterically as the lights flicker, and then leaps up and shoves Leah to the floor. Violet sees a figure standing over Leah, a bloody humanoid being, and it rips at Leah's face. When Violet turns on the lights, Tate is sitting in the chair, smiling, and Leah's face is bleeding. The girl runs off and Tate says that she won't bother Violet anymore. Violet asks what the figure was but Tate says that he didn't do anything. She shoves Tate back and tells him to get out. When she runs upstairs, Tate screams at her saying he thought she wasn't afraid of anything.
As Ben jogs, the burned man drives up behind him in a car. The man gets out and runs after Ben as he jogs down a forest path, but Ben gets behind him and demands to know who he is. The burned man says that Ben's family is in danger. They sit down and the man, Larry Harvey, says that the burns cover of his window. When Ben threatens to have him arrested, Larry says that he has inoperable brain cancer and that he was released from prison because of it. He admits that he committed a triple homicide and explains that he lived in the house and heard voices that drove him to kill his wife and two daughters. They told him to pour gasoline on his family and set them on fire, and he obeyed without question and watched them burn. Larry breaks into tears and then admits that he doesn't remember how he put himself out. He asks if Ben has been sleepwalking and tells him to read the transcript of his trial. Ben threatens to send him to a psychiatric hospital if he doesn't leave his family alone and runs off. As Ben goes, Larry smiles in satisfaction.
Constance slips into the Harmon house and tries on Vivien's earrings. Moira catches her and tells her to get out, but Constance says that they'll blame the new maid if anything goes missing. She tells Moira to move so that she doesn't have to kill her again.
Vivien returns home and finds Ben waiting for her. She says that she wants Indian food and he points out that she only likes that when he's pregnant. Vivien smiles and Ben realizes that she is pregnant and embraces her.