The Locked Door (2021) is a psychological thriller written by American novelist and physician Freida McFadden. The novel is narrated by surgeon Nora Davis (born Nora Nierling), whose father Aaron Nierling was a notorious serial killer when she was 11. Now an adult, Nora is horrified when a patient is killed following her father’s pattern, and must work to uncover the truth. Major themes in the novel include the lasting effects of trauma, the debate about the relationship between nature and nurture, and the difficulties of separating personal and professional identities.

Content Warning: The novel contains graphic depictions of violence, allusions to animal cruelty, and mentions of death by suicide.

This guide is based on the 2021 Hollywood Upstairs Press e-book edition.

Plot Summary

In the Prologue, narrator Nora Nierling describes how her father, Aaron, was arrested for the murder of 30 women. The chapters that follow alternate between the narrative present and events that happened 26 years ago. This plot summary is arranged chronologically for clarity.

Twenty-six years ago, Nora spent her 11th birthday blissfully unaware of her father’s crimes. Nora participates in bullying a classmate, Marjorie, then follows the girl home. At night, she lies awake listening to her parents fight about whether she needs therapy. One day, she finds a person locked in a cage in her father’s basement, whom she realizes is Mandy Johannsson, a local missing woman. Her father offers to teach her to be like him. Later, Nora lures Marjorie to an abandoned trail and chases her with a penknife. She corners her, but she can’t bring herself to hurt her. Nora convinces her friends to stop bullying Marjorie on the day her father is arrested for his crimes.

Twenty-six years later, Nora, now using the last name Davis, is a successful surgeon. When she rejects the advances of a former patient, Henry Callahan, he grows aggressive and follows her in his car. She manages to lose him and arranges to fire him from her practice. At home, she reluctantly feeds a stray cat that has been hanging around.

Nora suspects that another patient, Arnold Kellogg, is abusing his wife. She offers help, but his wife declines. Nora reconnects with Brady Mitchell, a college boyfriend who is now a bartender at her favorite bar, Christopher’s. Driving home one evening, she is followed by a driver who crashes as she tries to evade him. She reports the accident but does not intervene.

The next morning, Nora hears from the assistant at her practice, Harper, that Harper’s boyfriend has dumped her. Nora is visited by Detective Ed Barber, who reveals that Nora’s former patient, Amber Swanson, a dark-haired woman with blue eyes, has been found murdered with her hands cut off, following her father’s pattern.

Nora arranges a one-night stand with Brady at his house. She is spooked by his landlady, an elderly lady in a rocking chair on the front porch. After having sex with Brady and leaving, Nora remembers that she broke up with him because of his obsession with horror movies and true crime. When she arrives home, she finds a letter from her father without a postmark at her back door and immediately destroys it.

The next time Nora encounters Brady’s landlady, she warns her that she hears women screaming in Brady’s apartment. When Shelby Gillis, another patient with dark hair and blue eyes, is found dead with her hands cut off, Nora realizes she is being targeted. She also realizes that Harper has dark hair and blue eyes like her father’s victims and her dead patients.

After another sexual encounter with Brady, Nora discovers a young girl’s bedroom in his home. Brady explains that he shares custody of his five-year-old daughter, Ruby. Hurt that he didn’t tell her earlier, Nora leaves. The next day, she is confronted by Amber Swanson’s mother, who calls her Nora Nierling. Mrs. Swanson insists that Nora is involved in the murders and promises to go to the media.

Brady drives Nora home after her tires are slashed and prevents Detective Barber from searching her house. He leaves after learning the truth about Nora’s father. The stray cat leads Nora into her basement, where she finds blood. Nora cleans the blood, then performs a successful emergency surgery. Afterward, Detective Barber informs Nora and her new attorney, Patricia Holstein, that Nora’s prints were found in Shelby Gillis’s home. That night, Brady returns Nora’s car with new tires, and the pair share a painful goodbye.

After another letter appears at her back door, Nora visits her father in jail in Oregon to demand to know who killed her patients. He responds that she did, and he reveals that Nora killed her childhood pets, suggesting she is capable of murder. On her arrival back in San Francisco, she finds a severed hand in the trunk of her car and dumps it at a fast food restaurant.

Detective Barber visits to apologize for his accusations, but Nora suspects he’s trying to determine where she was all day. She declines to tell him or her colleague Philip where she has been. When she sees Henry Callahan unharmed at the hospital, Nora realizes someone else was following her the night of the crash. She identifies the man as William Bennett Jr. and visits him in the hospital. She recognizes him but cannot place him. Later, Arnold Kellogg’s wife informs Nora that Arnold died peacefully in his sleep.

Harper leaves the office with Philip, to Nora’s dismay. Nora also discovers that an appointment she made to have a home security system installed has been canceled, although she did not cancel it herself. Nora goes to Brady’s house, where she learns from his landlady that he does not have a daughter. This lie leads Nora to suspect that Brady is the murderer, and she leaves. When she realizes Brady couldn’t have canceled the security appointment, she begins to suspect Philip, who had access to her email and patient records.

Nora finds Philip unconscious and tied up in her basement with Harper holding him hostage. Harper reveals that she is Nora’s sister and that she has been setting Nora up with help from their father. She is arrested for the murders of Nora’s patients, and Nora and Brady reignite their relationship.

In the Epilogue, Nora and Brady start a new life together as an engaged couple, living together with Brady’s daughter, Ruby. The narrative switches briefly to Harper’s perspective, and she reveals that Nora assisted Mrs. Kellogg in poisoning her abusive husband. Harper keeps her sister’s secret as ammunition.