Under Her Care

In Tuscaloosa, Alabama, the body of Annabelle Chapman, the mayor's wife, is discovered on the riverbank of Hurricane Creek beneath an old railroad bridge. Standing next to the body, covered in her blood, is 14-year-old Mason Hill, a boy diagnosed with autism spectrum disorder and severe intellectual disability. His mother, Genevieve Hill, a wealthy former Miss Alabama and local celebrity, insists Mason stumbled upon Annabelle during a walk and tried to save her with CPR. Detective Layne, the lead investigator, recruits Casey Walker, a pediatric psychologist who specializes in autism, to help communicate with Mason and earn Genevieve's trust. Casey, a single mother whose nine-year-old daughter, Harper, also has autism, reluctantly agrees to serve as a paid consultant.

Casey's first encounter with Genevieve reveals a woman oscillating between terror, rage, and desperate charm. Genevieve insists a violent stranger she calls "That Monster" attacked Annabelle and now threatens her family. Mason is physically imposing at six foot one but behaviorally childlike, wearing red noise-canceling headphones and repeating phrases in perfect imitation of voices he has heard. Detective Layne shares confidential evidence: Annabelle's skull was bashed in with a rock, and Mason's fingerprints are the only ones on the weapon.

Casey reviews Mason's psychological and medical records, which confirm an autism diagnosis with an IQ of 38 and a mental age of approximately four. She also discovers disconnected psychiatric hospital notes referencing psychosis, seizures, and electroconvulsive therapy, none of which are typical for autism. A critical inconsistency emerges: If Mason truly functions at a four-year-old level, Genevieve would never have let him wander alone near a creek. Confronted at home, Genevieve admits she lied; Mason got away from her. Detective Layne also notes that Genevieve's clothes had no blood despite her claim of pulling Mason off the body. Genevieve ends the interview in fury.

Privately, Genevieve's perspective reveals she has been receiving threatening notes. She recalls that at the creek, a man emerged from behind a tree after she found Mason with Annabelle's body, threatened her, and forced the bloody rock into Mason's hands. Genevieve is torn between confiding in the police and fearing retaliation.

Casey travels to Tupelo, Mississippi, to meet Genevieve's 19-year-old daughter, Savannah, who has not visited home since the murder. Savannah describes a fractured relationship with Genevieve, who entered her in beauty pageants from age three and emotionally abandoned her at 10 when Savannah quit performing. Genevieve then shifted all her attention to Mason, obsessing over getting him diagnosed with autism. Savannah insists Mason was a normal child who suddenly lost his words and abilities. She denies Mason could have hurt anyone and suggests the police should look at Genevieve instead.

Casey makes a breakthrough in Mason's test records. Across five IQ tests over seven years, his scores are nearly identical, with the exact same wrong answers given in the same order. Casey concludes this pattern strongly suggests someone coached Mason to fail the tests to appear intellectually disabled. She devises a plan to test Mason herself, telling Genevieve she wants to assess trauma-related regression. When Casey deviates from the standardized protocol, Mason becomes distressed but correctly completes tasks he should not be able to do if truly impaired. Casey also notices bruises on his forearms in patterns resembling fingerprints.

Detective Layne files a child abuse report based on the bruises without warning Casey. A medical exam reveals fingertip bruises, old fractures, and burn scarring, and Mason is placed in emergency foster care. Genevieve retaliates by filing a report against Casey, alleging she witnessed Casey twisting Harper's arm in a parking lot. The claim stems from a confrontation where Genevieve ambushed Casey and Harper at Walmart, triggering a severe meltdown. Harper is temporarily removed from Casey's care while the report is investigated.

When Casey confronts Genevieve, Genevieve reveals the psychiatric hospital notes actually belong to Savannah, who was hospitalized multiple times starting at age 12 for psychotic episodes and suicide attempts. The records show Savannah experienced persecutory delusions about her mother during psychotic breaks but retracted all accusations once stabilized, leading Casey to question Savannah's claims about Genevieve. In a second meeting, however, Savannah insists Mason was developmentally normal before Genevieve began fabricating his diagnosis. She declares that Genevieve killed their father, John, who had told Savannah he planned to leave Genevieve shortly before his fatal heart attack.

Meanwhile, Genevieve calls the phone number on the threatening business cards and reaches a man claiming to be the boss of the attacker at the creek. He demands $300,000 in exchange for suppressing a video John allegedly sent him showing Genevieve torturing Mason. Genevieve begins withdrawing cash from banks across Birmingham. She also gives a televised interview admitting Mason did hit Annabelle with a rock but claims he was mimicking violence from another attacker, and she publicly names Casey as a conspirator against her family. Detective Layne formally charges Mason.

Casey refuses to give up. At his foster home, Mason is thriving far beyond what his diagnoses predicted. The foster home's psychiatrist discovers toxic levels of cholesterol-lowering medication in Mason's blood, suggesting Genevieve drugged him to keep him impaired. Casey introduces Mason to TouchChat, an assistive communication app, and he deliberately types a plea for help.

Casey follows Genevieve in a rental car to a wooded area near the Sipsey River swamp, where Genevieve meets a masked man and hands over the cash. Casey records the exchange from the brush. When the man refuses to delete the video and turns to leave, Genevieve fires a gun at him. Casey tackles her, causing the bullet to hit the man's leg. In the ensuing standoff, Genevieve holds Casey at gunpoint and confesses aloud that she considered Mason ordinary from infancy and fabricated his disabilities to make him extraordinary. Her internal monologue further reveals that she hired someone to stage a fake attack on Annabelle so Mason could rescue her and become a hero, but an unknown assailant appeared instead and killed Annabelle. Her thoughts also confirm she killed John after he discovered the hidden room where she tortured and trained Mason. Casey appeals to Genevieve's narcissism, tackles her, seizes the gun, and shoots her in the calf as Genevieve flees. Police arrive moments later.

The final twist shifts to Savannah's perspective. She and her boyfriend Brett, a fellow former patient at White Memorial psychiatric hospital whom she reconnected with at the University of Mississippi (Ole Miss), orchestrated the entire blackmail scheme. The attacker at the creek was never identified; Savannah and Brett invented a figure they called "Simon" to exploit Genevieve's guilt and paranoia. Brett posed as the note deliverer and the blackmailer's voice on the phone, with Savannah coaching every step. The threatening video was a bluff based on text messages Savannah found on her dead father's phone. With the $300,000 secured, Savannah injects the sleeping Brett with a fatal dose of heroin, stages the scene as a relapse, and walks out with the money, planning to disappear to California under a new name. She reflects coldly that she learned manipulation from her mother. The novel closes with Mason's voice, stronger and more coherent than in the fragmented interludes that appear throughout the book. He declares he is no longer under Genevieve's control and will tell the truth about everything, including how she killed his father with an injection between his toes.