While babysitting the daughter of Ed and Lorraine Warren, a teenager and her friend unknowingly awaken an evil spirit trapped in a doll.
After bringing home the infamous Annabelle doll, Ed and Lorraine Warren’s daughter Judy is something of an outcast at school due to her parents’ reputation. Ed and Lorraine go away for the night, leaving Judy in the care of her babysitter Mary Ellen. They are later joined by Mary Ellen’s friend Daniela, who goes with the intention of entering the Warrens’ museum of haunted artifacts to contact the spirit of her father, who died in a car accident that Daniela blames herself for. Unfortunately, she opens Annabelle’s case and forgets to lock it.
The demon doll begins to unleash spirits that possess the artifacts, like the Hellhound, the Ghost Bride, the Samurai, and the Ferryman. They attack the girls, plus Mary Ellen’s crush Bob. After enduring the spirits, the girls succeed in finding Annabelle and lock her back in her case.
After Ed and Lorraine come home, they celebrate Judy’s birthday with Mary Ellen, Daniela, Bob, and Judy’s classmates. Lorraine also confides to Daniela that she spoke to her father’s spirit, and he wants her to stop blaming herself for what happened.
In 1971, demonologists Ed and Lorraine Warren bring the possessed Annabelle doll to their home after some claims from two nurses, Debbie and Camilla, that the doll often performed violent activities in their apartment. The doll is placed in a sacred glass box in the couple’s artifacts room and blessed by Father Gordon, even though it attacked Ed through the other dead spirits on their way home when an accident occurred near a tunnel.
One year later, the Warrens welcome Mary Ellen, who will be in charge of babysitting the couple’s daughter, Judy, when they go overnight to investigate another case. Mary Ellen’s duty immediately begins with driving Judy to her school. At school, Judy sees a strange priest spirit, who begins following her. After shopping at her friend’s supermarket and meeting her crush, Bob Palmeri, Mary Ellen starts to bake a cake for Judy’s birthday. It is when her troubled and uninvited friend, Daniela, who is curious about speaking to the dead after the death of her father, comes to the house. Daniela gives a pair of roller skates to Judy as her birthday present and convinces her to play with Mary Ellen outside. While they are away, Daniela tries to get into the artifacts room but becomes devastated as the room is securely locked.
Daniela finds the door’s key in Ed’s working room and starts exploring and touching artifacts, ultimately trying to contact her late father with an artifact called the Mourner’s Bracelet. She accidentally leaves Annabelle’s glass box unlocked after a knock comes from it that makes her think that it was her father attempting to respond. The terror begins shortly afterward with a knock at the front, but there’s no one there. The spirit of Bee Mullins interrupts Mary Ellen. That night, Annabelle begins releasing other spirits, such as The Ferryman, The Bride, the Samurai Armour, a Feeley Meeley board game, and a Hellhound. When Bob asks Marry Ellen out for a date, he is attacked by the Hellhound. Shortly after, Mary Ellen was attacked and dragged by the Ferryman, while Judy is interrupted by Annabelle in her bedroom. When Daniela wants to return the artifacts room’s key, she is trapped inside the artifacts room and tormented by a monkey toy and an old TV that can predict the near future.
A future, bloody, and screaming Daniela appears on the TV screen after an old cursed telephone begins ringing. When the real Daniela reaches to grab the telephone, Judy and Mary Ellen escape from the ghouls and prevent Daniela for doing so. The trio eventually escapes from the artifacts room after Annabelle terrorizes them again. Judy explains that they must lock Annabelle in her case again so the other spirits will rest. When they attempt to retrieve the doll, Daniela is attacked and possessed by The Bride and starts attacking Mary Ellen. Eventually, Mary Ellen and Judy find the doll after the priest’s spirit, acting as Judy’s guardian, shows them the way. Daniela recovers thanks to Ed’s recording footage of The Bride exorcism and helps Mary Ellen and Judy recover the doll. They immediately retrieve the glass box’s key after they are attacked by demonic hands from the Feeley Meeley board game. After the doll’s case is locked, the disturbances stop and the other spirits return to their slumber. The trio is also reunited with Bob.
The next morning, Ed and Lorraine returns and the trio tell them about the event. Eventually, Daniela apologizes to Lorraine, but Lorraine knows that it’s because she wants to contact her late father. Lorraine received a message from Daniela’s father and tells her about it, and gives Daniela the Mourner’s Bracelet with promise for good purpose only. The two then reunite with the others to celebrate Judy’s birthday party along with Judy’s friends.
The film starts with Ed and Lorraine Warren (Patrick Wilson and Vera Farmiga) taking Annabelle away from a trio of friends who claim to have been haunted by her. On their way back home, they are told by an officer that the road is closed off due to an accident. Before turning back, Lorraine thinks she sees a young woman standing among the wreck.
The couple drive by a cemetery when the car breaks down. Ed goes to check out the hood, when Lorraine sees the ghost of the girl from the accident, telling Lorraine that she likes the doll. She then looks out by the cemetery and sees other spirits walking around. One of them pushes Ed into the street, causing him to nearly get hit by a truck. The driver comes out and says that it felt like the truck lost control. Lorraine deduces that Annabelle is responsible, as she is a beacon for spirits. They take her home and have her blessed by a priest before they lock her away. The text then states that the Warren home is known to house many sinister artifacts, but Annabelle is their most notorious and evil finding.
One year later, after the Warrens helped the Perrons get rid of Bathsheba, their daughter Judy (Mckenna Grace) feels isolated at school due to a recent article that questions the authenticity of her parents’ work. Kids at school decline invitations to her birthday party, and she is mocked by a classmate named Anthony Rios (Luca Luhan), until Judy’s babysitter Mary Ellen (Madison Iseman) comes to her defense. She is staying with Judy for the weekend while Ed and Lorraine are away on another case. Meanwhile, Judy sees what looks like a ghostly priest at the school, as she inherited her mother’s ability to see spirits..
Mary Ellen goes to the shop with her best friend Daniela (Katie Sarife), who is also Anthony’s older sister. They discuss Mary Ellen being at the Warren house, as well as the fact that her crush, Bob, AKA “Bob’s Got Balls” (Michael Cimino), is there working at the store. Mary Ellen chats with him for a bit before leaving, and Daniela lets Bob know that Mary Ellen likes him.
Daniela shows up at the Warren house with the intention of checking out their haunted museum, while Mary Ellen is baking a cake for Judy. Daniela gives Judy a pair of roller skates as a gift, so she and Mary Ellen go around the block to try them out. Daniela finds the keys to the museum, which is in the basement, and she enters. She starts checking out and touching the artifacts, but she takes one called the Mourner’s Bracelet. She calls out asking for a sign of a presence there with her, but specifically that of her father. As she starts to go back upstairs, she hears a thump. Annabelle has tipped over in her case. Daniela ignores the sign that says to not open the case under any circumstances, and she opens it to put Annabelle back up. She then hears the smoke alarm since she left the cake going in the oven for too long, which is found by Judy and Mary Ellen after Judy comes home due to scraping her knee. After she’s gone, Annabelle falls out of her case.
Daniela talks to her, and Judy learns that Anthony is her brother, but Daniela understands that he can be a jerk due to the experience they had over the past year. Moments later, Daniela thinks she sees her dad’s spirit in the house, but when she goes to look, she can’t find him. Judy then goes around her house, when she sees Annabelle sitting in a rocking chair for a brief moment. She enters the room, and the doll is gone. Then, a figure appearing as a ghostly bride starts to walk around. The spirit stalks Judy until it moves toward her with a dagger. She grabs a cross and screams, alerting the girls to come to her aid. Judy explains that she saw the ghost, as the dress that she wears is supposed to corrupt the person wearing it.
Daniela continues snooping over the Warrens’ work, and she finds several case files, including one on a man claiming that he was a werewolf (or a Hellhound, to be precise), and another of The Ferryman, who took coins in exchange for the souls of the dead, and the girl in the case file looks exactly like Mary Ellen. When Daniela asks Judy about Annabelle, the little girl refuses to discuss the evil doll.
Later, Bob shows up at the house after being invited by Daniela, just as a stoned pizza guy comes to make a delivery. He sees that Bob likes Mary Ellen, and he advises him to woo her with music. Afterwards, the girls cut Judy’s cake, and she invites them both to her birthday party, which they promise they will attend. Then, the girls hear Bob playing the guitar for Mary Ellen. Before she can join him outside, he is found by the Hellhound, and he runs to hide in the Warrens’ chicken coop. He is safe, but one wandering chicken becomes Hellhound food.
Mary Ellen goes to tuck Judy into bed. Judy asks her what happened to Daniela’s father, and Mary Ellen explains that he died in a car accident, and Daniela blames herself because she was driving. Later, Mary Ellen is in the kitchen when a glass slides off the table and breaks on its own. She hears a knocking at the door, and she finds the spirit of Annabelle “Bee” Mullins (Samara Lee) outside, and she mentions the doll. Mary Ellen goes to Judy’s room and finds Annabelle lying there next to her. Meanwhile, Daniela goes back into the museum after the door opens by itself. She sees her father’s spirit in the mirror, but when she turns to face him, his face is mutilated and he angrily blames her for his death. She goes to run out of there, but the door locks and traps her in there. She continues to wander and sees a TV that shows her moves before she makes them, and she is startled by a creepy monkey doll.
Mary Ellen walks around the house with a flashlight and finds coins on the floor. She investigates and is stalked by The Ferryman, who terrifies her when he makes his skeletal appearance. The spirit attempts to pull her towards him, but Mary Ellen uses her flashlight to make him disappear. She then runs to Judy’s room, frantically calling out to her, but she is still sleeping. Judy then feels something pulling her leg. She looks under her sheets to find Annabelle, plus the spirit of Annabelle Higgins screaming at her. Judy throws the doll against the wall, but the spinning color lights in her room move around and cast silhouettes of the doll rising, followed by Bee, Higgins, and finally the horned demon that uses Annabelle as a conduit. Judy runs out screaming and finds Mary Ellen. They attempt to call her parents, but what sounds like Lorraine’s voice becomes sinister as she asks to speak to Annabelle, and she tells the girls that the doll wants a soul.
The girls manage to get Daniela out of the museum, but she admits to them that she touched everything in there. Judy says Annabelle is responsible for all the hauntings, as she let the spirits out to come and possess the artifacts. They are separated as the hauntings become more intense. Daniela is stalked by the Bride, while Judy runs to the car and is chased by the Hellhound. Bob comes out and smashes his guitar against the Hellhound’s face, causing it to vanish. Mary Ellen is stalked by a haunted samurai armor, which lets her hear the noises of all the people the wearer killed. The armor nearly crushes her, but she gets out fine.
Judy and Mary Ellen try to find Annabelle after getting the key to her case inside a board game box that tries to attack them with demon hands. Daniela becomes possessed by the Bride and attacks Mary Ellen. Judy saves them by playing an exorcism video with Ed and Lorraine, which pulls the Bride out of Daniela. Judy is then led by the spirit of the priest to find Annabelle. The girls rush to the basement to put her away, but Judy is attacked by the horned demon. He attempts to take her soul, but Judy repels him with a cross. The girls then finally lock Annabelle in the case, and everything goes back to normal. Bob also comes out, and Judy says he saved her.
The next morning, Ed and Lorraine come home, and Bob has to leave, but Mary Ellen accepts his invitation to be his homecoming date.
Later, Judy’s party goes on with just her parents, but Mary Ellen and Daniela arrive with Bob, plus Judy’s classmates, including a now nicer Anthony. As the party goes on, Daniela privately talks to Lorraine. She tells her that she spoke to her father, who says he misses her and that she must stop blaming herself for what happened. Lorraine gives Daniela the Mourner’s Bracelet, and Daniela tearfully hugs her. They return to enjoy the party with Judy.
The film closes on a picture of the Warrens, which transitions into a photo of the real Warren family, and is followed by a dedication to Lorraine Warren.