The Intruder

The Intruder is a psychological thriller novel by internationally bestselling author Freida McFadden. Originally published in 2025 by Poisoned Pen Press, The Intruder is written from the alternating first-person points of view of Casey and Ella. Casey is a young woman living in the New Hampshire woods all alone. When a storm blows in one night, she is terrified to discover a young girl hiding in her toolshed. She is afraid of the girl but takes pity on her, much to her regret. Meanwhile, Ella is a young girl living alone with her abusive mother. Unable to free herself from her mother’s violence, Ella takes extreme measures to set herself free. Casey’s and Ella’s interlocking perspectives create narrative tension, while exploring the novel’s themes of Navigating the Psychological Effects of Trauma, The Relationship Between Fear and Trust, and The False Allure of Solitude.

This guide refers to the 2025 Poisoned Pen Press hardback edition of the novel.

Content Warning: The source material and guide feature depictions of child abuse, physical abuse, emotional abuse, substance use, graphic violence, bullying, mental illness, death, and sexual content.

Plot Summary

The Intruder is written from Casey’s and Ella’s alternating first-person points of view and shifts between the narrative past and present. Casey’s chapters are labeled as “Now” and set in the present, while Ella’s chapters are labeled as “Before” and set in the past.

In the narrative present, Casey is living in a cabin in the woods by herself. One night, a storm blows in. She asks her landlord Rudy to fix the leaky roof and handle the wavering tree out front, but he does nothing. Her kindly, attractive neighbor Lee Traynor stops over to see if she will make it through the storm. Casey thinks Lee is nice, but she distrusts him on principle and dismisses him from the cabin without accepting his help.

As the storm blows in, Casey tries to prepare. She tapes her windows shut and sets up candles. She then notices a face in the window, which disappears a moment later. Unable to explain the apparition, Casey decides she was hallucinating. Shortly thereafter, she is overcome by fear once more when she looks up and sees a light on in her shed. Carrying her gun, she investigates the shed and discovers a young, emaciated girl inside covered in blood. Despite her better judgment, Casey invites her inside.

The narrative shifts into the past, where Ella is a teenager living with her mother Desiree. Desiree is a person who hoards. Their house is filled with unnecessary collectibles, outdated paperwork, and rotting food. Ella can never find appropriate clothes to wear or food to eat. At school one day, she is sent to the principal’s office for stealing another kid’s lunch. She runs into two classmates at the office: the troublemaker Anton Peterson, who berates her for smelling bad, and the perfect, popular girl Brittany Carter, whose life Ella envies.

Ella and Anton are assigned as partners on a science project after, but Anton refuses to work with Ella and insists she do the project alone. Ella resigns herself to being hated by everyone. On her way home from school later, she encounters Anton in the park. She is shocked to see that another bully named Devin is beating him up. When Devin pulls a knife on Anton, Ella smashes Devin over the head with a rock. She and Anton flee to her house. Ella is initially embarrassed to let Anton inside to clean up after the fight, but Anton doesn’t make fun of her for the mess. After he leaves, Desiree returns and discovers the cigarette Anton was smoking on the coffee table. Ella takes the blame, and Desiree burns her with the cigarette as punishment.

Back in the present, Casey tries to gain the young girl’s trust by feeding her pasta and cookies. The girl clutches a blade while eating. Casey is worried because the girl’s clothes and backpack are bloody, and she’s covered in bruises. However, she knows she needs to make the girl like her before figuring out what she has done and where she is headed. She notices her knife is engraved with the name “Eleanor” and starts telling Eleanor about Lee to break the ice between them.

Casey tries settling Eleanor for bed. While Eleanor is falling asleep, Casey digs through her bag and finds a notebook filled with sinister drawings. Convinced Eleanor is there to kill her, Casey goes to retrieve her gun, suddenly remembering she left it in the room with Eleanor. She opens the door, and Eleanor threatens her at gunpoint. She then ties up Casey and flees the cabin to complete her real nefarious mission.

The narrative shifts back into the past. Over the following weeks, Ella and Anton become close friends. Anton stops bullying Ella and even starts confiding in and defending her. He teaches her to pick locks, as he did with his younger brother Brad, so she can escape when Desiree locks her in the closet. He invites her over to his house, offers her food for lunch, and gives her a silver chain. Anton doesn’t judge Ella either when she goes on a hunt for her biological father—whose name she discovered on her secret birth certificate in Desiree’s room.

One day, Brittany bullies Ella for thinking they had the same dad. Anton races to Ella’s defense and pummels Brittany with a rock. He is put into juvenile detention thereafter. Ella is distraught over losing her only friend. That night, she lights her house on fire with her mother inside. The house burns down, and Desiree dies. Not long later, child protective services locates Ella’s biological father and she moves in with him. They develop a close relationship.

The “Ella” in the narrative past is revealed to be Casey as a child, not Eleanor as was previously implied; the intruder in Casey’s house is a different girl. In the narrative present, Casey realizes that Eleanor is going to kill Lee. She has deduced that Lee must be Eleanor’s biological father, and she has come here to murder him for abandoning her as a child. Remembering Desiree’s death, Casey races to Lee’s cabin to stop her. She doesn’t want Eleanor to make the same mistake she did.

Casey prevents Lee’s murder. When Lee learns what’s going on, he explains that he is really Eleanor’s uncle; his brother had a sexual relationship with Eleanor’s mother but has since died. Eleanor is distraught that she never got to meet her biological father, but Lee soon assumes the role of her legal guardian. Over the following months, Lee, Casey, and Eleanor create a life in the woods together.

The narrative shifts into Lee’s perspective, revealing that he is Anton’s younger brother Brad but has changed his name. Anton is Eleanor’s father and is still alive. Anton made Lee promise to tell anyone who asks about him that he is dead. Anton has been incarcerated ever since killing his and Lee’s father. He tasked Lee with looking after Casey. One day, Lee goes to the prison to visit Anton. Lee has fallen in love with Casey and is waiting for the right time to ask Anton for his blessing to be with her.