This story takes place in the late 1980s with many flashbacks to earlier years. Sylvie Mason lived with her parents, Rose and Sylvester, investigators of the paranormal, until their murder in February of 1989. Called to an abandoned church by Sylvie’s older sister, who had run away, both Rose and Sylvester are shot. When Sylvie enters the church, she is struck on the head and falls unconscious.
After hours of police interrogation, Sylvie claims to have seen Albert Lynch, a disgruntled client of her parents, after she was attacked. Lynch’s fingerprints were found at the scene, and with Sylvie’s testimony, the police assure her that he will be convicted of the crime. But Sylvie only claimed to have seen him because the police convinced her it was the only way to arrest him.
Sylvie now lives in her childhood home with her older sister, Rose, who is her guardian. Sylvie is a freshman in high school, but has no friends. The other students avoid her because of the rumor that her house is filled with possessed objects.
Rose is self-absorbed and angry at how her life has turned out. She barely takes care of Sylvie, who eats Popsicles for dinner and potato chips for breakfast. As the trial of Albert Lynch approaches, Sylvie reads in a newspaper report that he has an alibi for the time of the murders. He admits to having met with Sylvie’s parents in the church, but insists he left them unharmed. An older man claims to have seen Lynch in a convenience store bathroom. Lynch helped catch the man’s dog a few minutes later. Sylvie is determined to piece together clues about that night. She writes out her thoughts in a diary that was given to her by her school counselor.
Sylvie recalls the first time she met Albert Lynch. Her parents had brought her and Rose with them on a speaking engagement in Florida. Until then, they had hired nannies to care for the children when they were out of town, but Rose had locked the last nanny in the bathroom for two days without food.
Rose argued religion with her parents on the long car ride from Maryland to Florida. She read from the Bible and ridiculed passages. At the speaking engagement, Rose and Sylvie were supposed to wait in a separate room while their parents gave their presentation, but they snuck into the auditorium. A man stood up to challenge Sylvester’s claims of the paranormal. After a short exchange, Sylvester introduced the man as his estranged brother, Howard. The girls followed Howard to the parking lot when he stormed from the building.
Their mother tried to convince Rose to stay, but she chose to leave with Uncle Howard. It is then that Sylvie and her mother saw Albert Lynch. He seemed to be talking to a bush. He approached Sylvie’s mother and asked for her help. She went to the bush and began to hum a soothing melody. She then held out her hand and helped a young girl of about 13 step out from the bushes. Lynch was amazed and left grateful for his daughter’s apparent return to sanity.
Sylvie and her parents spent hours looking for Rose, only to find her back in their hotel room. Sylvester took her outside to talk. When she returned, she seemed to be a different person, now quiet and submissive to their parents but Sylvie suspected it was an act.
In the present time, Sylvie makes friends with a former boyfriend of her sister’s, a man named Dereck. He helps to raise and slaughter turkeys on the farm next to her house. Sylvie also makes contact with a reporter named Samuel Heekin, who wrote an article and book about the Masons and their work. Sylvie believes Mr. Heekin might be able to help her understand her parents better.
Sylvie recalls that two years after the incident in Florida, the girls once again accompanied their parents on a trip. This time, they drove to a house in Ohio. Sylvie and Rose were instructed to spend the day at the movies while their parents helped whoever was inside. Their parents then insisted they leave immediately for home instead of spending the night at a hotel as they had planned.
Their mother carried a large rag doll in her lap the entire time. The doll’s name was Penny, and strange things began to happen in the house when they brought the doll into their home. Sylvie would find her prized model horses in pieces, and their mother seemed like a zombie, unable to cook dinner or even get out of bed.
Mr. Heekin tells Sylvie that he has found her Uncle Howard. He lives in a nearby town. Heekin agrees to take her to visit him, although Sylvie knows her uncle does not want to see her. At first reluctant to speak with her, Howard eventually tells Sylvie that he is hoping to one day gain custody of her. He inherited their family’s old movie house and hopes to restore it to an auditorium. Howard then shows Sylvie how he tricked her father into believing there were ghosts by reflecting lights around the theater. Her father would never admit that the things he had seen as a boy were not real ghosts, even after Howard admitted the prank to him.
Mr. Heekin drops Sylvie back at her house, but she goes for a walk before going inside. When she returns, she sees a woman dropping off food. Rose would never let Sylvie eat the anonymous dinners left outside, claiming they were probably poisoned by people who hated their parents.
Curious, Sylvie sneaks into the woman’s car and hides in the back. As the woman drives them away, Sylvie remembers how her father sent Rose away to St. Julia’s, a home for troubled girls. That same day, Albert Lynch dropped his daughter off at their house to see if the Masons could heal her again.
Although guests usually stayed in a room in the basement, Abigail took over Rose’s room and even wore her clothes. Eventually, Abigail admitted to Sylvie that she faked her demonic possession so that she could get away from her father. She told Sylvie she was capable of doing awful things to people to get her way.
Abigail begged Sylvie to give her the prize money she had won for an essay so that she could run away before her father came back for her, implying that if Sylvie did not, she would hurt her. Abigail pierced her own hands to create wounds like stigmata. That same day, Rose escaped from St. Julia’s. She was appalled that Abigail had taken her place within the home.
Abigail left Sylvie’s home, spending the night at the parish priest’s rectory before disappearing. When the car that Sylvie hid in finally stops, Sylvie approaches the woman. She discovers the woman is Emily Sanino. Her daughter and Rose became friends at St. Julia’s. Emily’s daughter ran away and has not been seen since. Emily seems secretive and tells Sylvie not to tell Rose she has seen her.
Sylvie calls Dereck to give her a ride home. He brings an old newspaper clipping about an accident in which he lost two fingers. A deck collapsed under a group of teenagers having a party. As Sylvie studies the picture, she finds her sister, Rose, in the crowd. She also sees Emily Sanino’s daughter, Franky. Sylvie realizes Rose and Franky were lovers. St. Julia’s was a facility to rehabilitate homosexual teenagers. Sylvie arranges to speak with Albert Lynch, who swears to her he did not kill her parents. After putting all the pieces together, Sylvie confronts Rose with what she has discovered.
Rose admits that she and Franky had hoped to one day live together. She had run into Albert Lynch at a bar and taken his bribe to call her parents to meet at the church. He had threatened the Masons with a gun, demanding to know where Abigail had gone. Convinced by their mother that they did not know her whereabouts, he left the gun behind and fled the church.
Franky entered and tried to persuade the Masons to accept her and Rose’s relationship. When they refused, Franky shot them with Lynch’s gun. She then hit Sylvie. Franky has been living in their basement to hide from the police.
Unstable, Franky tries to kill Sylvie to keep her from telling the truth. Sylvie defends herself by hitting Franky in the head with a rock. When Franky falls unconscious, Sylvie runs to Dereck’s farm. When they return to Sylvie’s house, Franky is dead, and Rose has run away. Sylvie is sent to live with a foster family until her Uncle Howard can gain custody of her.