Sundial

The novel alternates between the perspectives of Rob, a suburban mother and fourth-grade teacher, and her 12-year-old daughter, Callie, with extended flashbacks to Rob's traumatic youth. Interspersed throughout are chapters from a fictional boarding school series that Rob writes in secret, whose characters and plots mirror the real narrative.

Rob lives with her husband Irving, a science professor, and their two daughters in a carefully maintained suburban home. Callie is emotionally flat and unsettlingly close to her father, while nine-year-old Annie is a fragile child and Rob's clear favorite. When Annie develops chicken pox, Rob realizes the infection could only have come from the neighbors' recently ill son, confirming that Irving is having an affair with their neighbor Hannah Goodwin. Their marriage is defined by Irving's serial infidelity, controlling behavior, and a history of physical and emotional abuse.

Annie is found shaking and vomiting after ingesting Irving's diabetes pills. Rob induces vomiting and saves her, then realizes Annie could not have opened the childproof cap while wearing mittens taped over her hands. Searching Callie's room, Rob finds a hidden backpack containing a decomposing squirrel, bone collages glued to anatomical drawings, and the missing pill-bottle cap. Callie confesses she has always killed animals. Rob decides to take Callie to Sundial, the family's remote desert property in the Mojave, to confront the crisis away from Annie, and asks Hannah to watch over Annie.

Callie's chapters reveal her inner world. She perceives two spectral companions: Pale Callie, a translucent figure who has always been with her, and Dumpster Puppy, a ghost dog whose bones she carries. She recalls Irving's warning that Rob is "unstable" and grows increasingly afraid at Sundial, noticing that Rob has emptied the knife drawer and dug a grave-sized hole outside the house. In a kitchen drawer, Callie finds a broken device later revealed to be Mia's old dog-training remote.

Sundial is a circular stone house deep in the Mojave, built by Rob's father Falcon and enclosed by miles of chain-link fence. The property includes abandoned dog pens and laboratories. Rob throws cheap meat over the fence as offerings to whatever lives beyond and visits the property's human sundial at dawn to mourn.

Over several days, Rob tells Callie the story of her past. As a teenager, Rob lived at Sundial with her fraternal twin Jack, their father Falcon, his partner Mia, and a caretaker named Pawel. Falcon and Mia studied dogs carrying a genetic variant called the "warrior gene," implanting electrodes to modify behavior through brain stimulation. Weekly "Sacrifice" rituals around a firepit allowed family members to symbolically burn painful memories. Jack grew increasingly erratic, seeing ghost dogs, biting Rob, and attempting to run away with a young research assistant. The escape failed when Mia caught them.

Jack's condition worsened. She slashed her own wrist, and a hospital blood test revealed that neither twin could be Falcon's biological child. Jack revealed they were adopted and that she had invented a gentle mother named Lily to give Rob a comforting fiction.

Rob left for college in Cielo, where she met Irving Cussen, the same research assistant who had tried to flee with Jack. They became engaged, but when Rob brought Irving to Sundial, Jack told Rob she had slept with him. Rob broke off the engagement and returned to college, where she befriended Asia, a dorm neighbor. Jack arrived pregnant with Irving's child, and Rob returned to Sundial to care for her. Rob was secretly pregnant herself. During a violent episode, Jack attacked Rob, causing her to miscarry. Rob buried her lost baby, whom she called Callie, beneath the sundial.

Mia then revealed the full truth. The twins were not from Nebraska. As small children, they had been imprisoned in cages at the nearby Grainger property, a place of horrific child abuse locally known as the "puppy farm," run by Jacqueline and Robert Grainger. Rob had killed one of the captors to escape. The twins walked into the desert and were found at Sundial's fence, both nonverbal, violent, and severely traumatized.

Falcon and Mia performed what they called "the click" on the twins: experimental genetic editing using engineered bacteria to suppress the gene associated with violent behavior. They had previously tested the procedure on dogs and on Pawel, a convicted mass murderer from Poland. The click held for Rob but began to fail in Jack, causing hallucinations and dangerous behavior. Mia warned that such genetic changes could be inherited, meaning Jack's child might carry the degraded genes.

Jack gave birth to a daughter, whom Rob named Callie after her own lost child. Jack deliberately provoked an aggressive rottweiler called Twenty-Three to test whether a repair to the click held under stress. The dog broke into the house and killed both Falcon and Mia. Jack lured it away from Rob and the baby, killing the dog but dying from her injuries. Rob staged the scene to look like a dog attack, released the remaining dogs into the desert, and buried Jack by the sundial. Rob later unearthed a hidden letter from Jack that described the horror of their captivity and revealed that the twins had named themselves after their captors: Rob for Robert, Jack for Jacqueline.

Irving arrived after Asia contacted him, recognized the baby as his biological daughter, and threatened to take her. Rob agreed to marry him, creating the suburban life described in the novel's opening. She raised Jack's daughter as her own and later had Annie with Irving.

Back in the present at Sundial, Rob takes Callie on a hike and confronts her about the bones and the killings. Pushed to honesty, Callie admits it will happen again, cementing Rob's resolve about her true plan. Rob reveals she never intended to use the click on Callie. She emptied the syringe and instead plans to kill Irving by injecting air into his bloodstream, provoking him into driving to Sundial through a calculated series of text messages. The grave Callie saw was dug for Irving, not for her.

When Rob tries to lock Callie safely in her bedroom, Callie reverses the trap and flees. Irving arrives by car and beats Rob severely. Callie frantically presses buttons on the old dog-training controller. Rob wrestles Irving to the ground, stabs him in the eye with the empty hypodermic, and strikes him with a cow femur that Callie throws to her. The aged coyote Thirty-One and his pack, descendants of the Sundial dogs, emerge from the darkness and drag Irving's body away. Pale Callie fades, telling Callie her time is done.

Callie then reveals the novel's final twist: Annie, not Callie, has been killing animals all along. Callie has been covering for her younger sister. Annie planted the pill-bottle cap in Callie's hiding place, framed Callie for the poisoning attempt, and has been storing Irving's diabetes medication inside Annie's pink star lamp, planning to use it against Hannah, whom Annie blames for threatening her parents' marriage. Annie took the lamp to Hannah's house.

Rob disposes of Irving's car in a mine shaft. She and Callie race through the night back to their suburb, arriving after two a.m. Callie reflects that protecting Annie will be her life's burden and mourns the loss of Pale Callie, whom she now understands to be the ghost of Rob's miscarried baby. The street is dark except for a single light: the pink star lamp, shining from an upstairs window of Hannah Goodwin's house, where Annie waits alone with Hannah.