A year before Ed and Lorraine’s experience with Annabelle, John and Mia Form of Santa Monica are expecting their first child soon. After a discussion with their neighbors, whose daughter Annabelle ran away two years earlier, John buys a large vintage doll that completes a set Mia has been building for years. That night, Annabelle, who had joined a Satanic cult, murders her parents with a male cult member, before they also attack John and Mia, with the man stabbing Mia in the belly before he’s shot by a cop. Annabelle runs into the bedroom and slits her own throat while holding the doll.
Mia’s baby is determined to have survived the attack, but she’s put on bed rest. The first night, their sewing machine turns on by itself and John also finds the doll out of its usual place on a rocking chair. He throws it out after Mia can’t stand looking at it anymore, but after he leaves for work, the stove turns itself on and starts a fire, in addition to an unseen force briefly pulling her backwards across the floor, with the stress prompting her into labor. Luckily, their daughter Leah is born without further complications, though Mia insists they move.
After getting to their new apartment in Pasadena, they find the doll in one of the boxes, which Mia takes as a sign she should keep it. They make a new friend in bookstore owner Evelyn, but more disturbing events keep occurring to Mia: she finds sequential drawings of Leah being killed by a truck, the spirit of a young Annabelle suddenly turns into a grown version and pushes her against the wall, and a baby carriage appears in the basement where a hand reaches out and grabs her, leaving her with a symbol etched in the skin which disappears when she escapes.
Mia finds the symbol while looking up Annabelle’s cult, and discusses it with Evelyn, who reveals she tried to commit suicide after causing a car accident that killed her daughter, but then heard her daughter say she needed to keep living. The couple’s priest Father Perez is also told about the doll and takes it himself, but Annabelle’s spirit attacks him and puts him in the hospital, where he tells John he saw the plan of the demon that the cult summoned, to use Leah to get Mia to offer her soul.
Mia and Evelyn return to the apartment together where they’re again attacked by the demon, and eventually Leah disappears with a message for Mia to kill herself while holding the doll to exchange her life for her daughter’s. John returns in time to save her, and Evelyn picks up the doll and sacrifices herself, causing Leah to safely reappear while the doll vanishes from beside Evelyn’s body.
Six months later, John and Mia have recovered completely from the experience and regained their happy lives, while the Annabelle doll appears in an antique store, where a woman buys it for her daughter, leading to the situation where Ed and Lorraine will be called in.
