The Wrong Daughter

Dandy Smith’s The Wrong Daughter (2025) is a domestic suspense novel that falls within the psychological thriller genre. The story centers on Caitlin Arden, a young woman whose life has been defined by the abduction of her older sister, Olivia, 16 years earlier. When a woman claiming to be Olivia suddenly returns, the family’s fragile peace is shattered. As Caitlin grapples with the surreal reunion, she begins to notice inconsistencies in the woman’s story and behavior, leading her to suspect that she’s an impostor. This forces Caitlin to confront her own traumatic memories and question the truth of what really happened on the night her sister disappeared.

Smith is known for psychological thrillers that focus on complex female relationships and dark secrets, including her internationally best-selling debut, One Small Mistake (2021), and The Perfect Match (2026). A resident of Somerset, England, Smith uses her local landscape as a primary setting, creating an idyllic backdrop for sinister events. The Wrong Daughter explores themes that include The Malleability of Identity in the Face of Trauma, The Corrosive Nature of Secrets and Deception, and Sibling Relationships as Both Sanctuaries and Battlegrounds.

This guide refers to the 2025 Kensington Books trade paperback edition.

Content Warning: The source text and this guide feature depictions of graphic violence, physical abuse, emotional abuse, mental illness, child abuse, sexual situations, incest, substance use, death, and death by suicide.

Plot Summary

In a peaceful Somerset town called Stonemill, sisters Olivia Arden, 13, and Caitlin Arden, 10, are home alone. They leave their unlocked house for a picnic in a wildflower meadow, where Caitlin admires her confident older sister. After they return home, Caitlin finds a green velvet journal (with embroidery depicting a gold bee) on Olivia’s dressing table. Olivia explains that it was a gift from “‘the boy on the bus’” (3), who told her to write everything down. That night, Caitlin is woken by a noise. She sees a tall man in a Venetian mask leading Olivia downstairs, holding a knife to her throat. Olivia spots Caitlin hiding and silently signals for her to stay quiet. The man places a matching green-and-gold mask over Olivia’s face before taking her out the back door. Caitlin hides until her parents, Clara and Myles, return and find that Olivia and her journal are gone. The police search for the “boy on the bus” but never find him.

Sixteen years later, Caitlin is 26 and works as a primary schoolteacher. She uses the surname of her fiancé, Oscar Fairview, to distance herself from the tragedy. On the eve of the 16th anniversary of Olivia’s disappearance, she runs into Laura, one of Olivia’s childhood friends. Laura recognizes Caitlin and begins reminiscing about Olivia, which makes Caitlin feel upset. Later, she meets her best friend, Florence, for their annual drink and confesses her reluctance to plan her wedding to Oscar, citing her mother’s anxiety and her own guilt. Later that night, memories of the abduction plague her. In the early hours, her father calls with shocking news: Olivia has returned.

A parallel storyline introduces 17-year-old Elinor Ledbury and her brother, Heath, 20, who live in the isolated Ledbury Hall. They’re wards of their uncle, Robert Brent, who controls their inheritance. They believe that Robert murdered their parents in a boating accident years ago. Heath’s frequent absences cause Elinor intense loneliness. When Robert makes an unexpected visit, tension grows between him and the defiant Heath. Elinor later follows Heath into town, where she meets Flynn Healy and discovers that Heath is secretly dating Flynn’s cousin, deepening her isolation.

Caitlin’s storyline resumes. She and Oscar rush to her parents’ house and meet a woman who claims to be Olivia, though her calm demeanor unsettles Caitlin. Olivia refuses to involve the police, and, to Caitlin’s horror, her parents agree. Olivia doesn’t remember the green journal or the boy on the bus. When Caitlin points out that Olivia is showering and washing away potential evidence, her parents again dismiss her concerns. Later, at Florence’s apartment, Caitlin sees a man in a midnight-blue Venetian mask watching the building. Feeling panicked, she tells Florence that Olivia is back and calls the police against her family’s wishes.

When the media swarm the Arden home, Caitlin’s father is furious. Olivia manipulates their mother into leaving so that she and Caitlin can sneak out to go shopping. As they travel through the woods, Olivia refers to a shed built six years after her disappearance as a landmark. In a bridal boutique, Caitlin tries on wedding gowns and is shocked to hear Olivia whisper to herself that another gown is “‘[j]ust like mine’” (91). Caitlin later sees a man in black, who she thinks is the masked man, following Olivia. When they return home, their parents are angry, and their father accuses Caitlin of attention-seeking. Feeling betrayed, she leaves. Oscar takes her on a trip to St. Ives, and she tells him about Olivia’s apparent marriage. Oscar says the captor’s name is Simon Briggs, claiming that a police contact told him. Caitlin begins seeing Olivia’s therapist, Dr. Gideon Temple.

In the Ledbury Hall timeline, Robert hosts a party to save his job, but Elinor ruins the party by accidentally setting fire to the curtains. Weeks later, Robert returns and brutally attacks Heath with a lead pipe. Elinor begins a relationship with Flynn, but Heath finds them and violently attacks Flynn, lying that Elinor is only 15. Heath reveals that he thinks Robert will kill them for the estate. When Robert returns, drunk and despondent, Heath shoots and kills him. They bury the body in the woods. Heath becomes paranoid and violent. When Elinor tries to run away, he drowns her in the lake.

Caitlin moves back into Blossom Hill House. She overhears Olivia on a secret phone and later sees the masked man at the kitchen window, but no one believes her. The masked man attacks Caitlin at her own house, but the police find no evidence, and Oscar’s doubt causes a rift between them. Caitlin meets Gideon in a park, where she sees the masked man again. A friend, Gemma, reveals that she saw Oscar with Olivia when he claimed to be in London. An anonymous package arrives, containing a book manuscript, and Caitlin later finds a note reading, “You needed to know. See you soon” (245). Caitlin confronts Oscar, who confesses that he’s the boy on the bus and that the book is about the Arden case. He refuses to pull the book from publication, and they break up. At brunch with Caitlin, Florence reveals that Olivia is now her joint maid of honor. Caitlin shares her impostor theory, but Florence dismisses it. News breaks that Simon Briggs was found dead from thallium poisoning.

The night before Florence’s wedding, Olivia warns Caitlin, “He’s watching you. […] Run” (247). On the wedding day, Caitlin is late because Olivia gave her the wrong room number. During the ceremony, Olivia whispers a threat, claiming that the real Olivia is dead. Enraged and grief-stricken, Caitlin attacks Olivia, ruining the wedding. In the car park, her parents reveal that a second, conclusive DNA test confirmed that the woman is Olivia. Believing that she has had a mental health crisis, Caitlin flees and calls Gideon for help. He saves her from being hit by a car and takes her to his house. Gideon encourages Caitlin to travel. She returns home and books a flight, but Olivia calls, offering answers if Caitlin meets her alone in the woods. Caitlin agrees but arranges for Gideon to be there as backup.

In the woods, Caitlin finds Gideon’s seemingly dead body and is abducted by the masked man, who unmasks as Heath Ledbury, who had been impersonating Gideon all along. Caitlin awakens handcuffed in Ledbury Hall and meets Bryony, another captive. The text reveals that Olivia wasn’t an imposter but was always the real Olivia, and she is in love with Heath. Heath kidnapped Olivia and Bryony because of their resemblance to Elinor, and Olivia asked him to bring Caitlin to her. Heath confirms his plan to fake Caitlin’s death by suicide and admits that he poisoned Simon Briggs. Caitlin and Bryony plot an escape. Caitlin locks Olivia in the wine cellar to steal the keys, but Heath returns. Caitlin kills him with a marble bust. Grief-stricken, Olivia attacks Caitlin on the roof, but Bryony intervenes, pushing Olivia to her death. Caitlin holds her dying sister in her arms.

One year later, Caitlin writes in a journal addressed to Olivia. Oscar’s book is a bestseller, but he’s estranged from the family. Caitlin and Florence are no longer friends, but Caitlin has reconciled with her parents. The police found the remains of Elinor Ledbury at the manor. Bryony was cleared of Olivia’s murder and has reunited with her own sister. Having found a measure of peace, Caitlin is at the airport, about to embark on a six-month trip to travel the world and fulfill her dream.