A Stranger in the House

A Stranger in the House (2017) is a domestic thriller mystery by Shari Lapena. One August night, wealthy suburbanite Karen Krupp runs out of the house in a panic and ends up driving her car into a utility pole in the bad part of town. She has no memory of how she ended up there or what happened before the accident. That same night, a mysterious man is found dead near the scene of her accident. As detectives piece together the series of events that led to his murder, Karen’s dark past is exposed. The novel explores The Impact of Secrets on Relationships, The Reinvention of Identity, and the darkness that lurks behind The Façade of Suburban Perfection.

Shari Lapena is the author of several domestic thrillers, including the best-selling The Couple Next Door, Not a Happy Family, Everyone Here is Lying, and Someone We Know. She lives in Toronto.

This guide uses the 2018 Penguin Kindle e-book edition.

Content Warning: The source material and guide feature depictions of death by suicide, domestic abuse, graphic scenes of death and injury, and mental illness.

Plot Summary

A Stranger in the House opens with Karen Krupp rushing to her car and driving away at a high speed. She crashes into a utility pole and loses consciousness.

Soon after the accident, her husband Tom Krupp returns home to find his wife missing. A police officer arrives to tell him that his wife has been badly injured in a car accident. He goes to the hospital to identify Karen. She has post-traumatic retrograde amnesia and does not remember anything that happened before the accident. Her friend and neighbor Brigid comes to visit her in the hospital. That night, two teenagers find the body of a dead man in an abandoned restaurant near where Karen crashed her car. Before she is discharged, the doctor asks Karen if she knows why she was saying the name “Robert” when she was admitted. She claims not to know who Robert is. The police charge Karen with reckless driving.

Three days later, Karen returns home from the hospital. She feels uneasy in her house because for months she has suspected that someone has been rummaging through their things when they are out. The next day, after a meeting with a lawyer about the reckless driving charge, Karen returns home to find a water glass next to the sink. She is sure it was not there when she left. She panics and calls Brigid, who in turn calls Tom. Tom reassures Karen that she is simply misremembering where the cup was when they left.

Meanwhile, Detective Rasbach is called to the crime scene in the restaurant. The dead man has been shot three times. He finds a pair of pink rubber gloves in a nearby parking lot. He learns that Karen got in a car accident nearby around the time the man was killed. Detective Rasbach and his partner Jennings question Karen. She denies knowing who the man is or missing any gloves. The detectives do not believe her. They interview Brigid, who claims she was not at home at the time of the incident. Detective Rasbach does a background check on Karen and learns that Karen Krupp is likely a false identity. He also learns that Karen received a call from a burner phone shortly before the incident.

Brigid calls Tom and tells him that the afternoon before Karen got in the accident, a mysterious man who claimed to be an “old friend” of Karen “from another life” (102) had been poking around the Krupp house. She also suggests that Karen might be living under a false identity.

The detectives question Tom and Karen again. They point out that on the night of the accident, Tom left work at 8:20 p.m. but did not return home until 9:20 p.m. They ask what he was doing for that hour. He claims he was simply “driving around,” but Karen does not believe him.

Karen and Tom drive to the crime scene to see if it will trigger Karen’s memory. Later that night, Karen remembers that the dead man, Robert Traynor, had called her and asked to meet. She assumes that it was Robert who was entering their house and going through her things. She remembers that after the phone call, she had taken her pink rubber gloves and unregistered gun and gone to meet Robert at the abandoned restaurant. She does not remember what happened after that. Karen reveals that Robert Traynor was her first husband. She had faked a death by suicide and started a new life under an assumed identity to escape him.

The next day, the detectives interview Tom at his office. He confesses that he had an affair with Brigid before he met Karen. He also admits that he was supposed to meet Brigid the night of the accident because she wanted to tell him about the strange man near the house, but she did not show up.

After the interview with Tom, Detective Rasbach calls Karen and asks her to come in for an interview. She panics and begins to pack a bag to run away. Tom comes home and stops her. Karen tells Tom that the dead man is her first husband, Robert Traynor. She says she had to fake her death and adopt a new identity to get away from him because Robert was abusive. She tells Tom she was shocked when Robert found her. She was afraid Robert would hurt Tom, which is why she went to meet Robert at the abandoned restaurant. However, she insists she did not murder Robert.

The detectives get a tip and are able to identify the dead man as Robert Traynor. They realize that Georgina Traynor, Robert’s “late” wife, is in fact Karen Krupp.

That night, Karen realizes that the stopper on her perfume has been moved. She realizes that Robert could not be the stalker because he is dead. Meanwhile, Brigid watches the Krupp house from across the street. She is furious that Tom ended their affair and she is plotting to get him back. It is revealed that Brigid is the one entering the Krupp residence with a spare key she had secretly copied. She enjoys going through Karen’s things and hopes to adopt her identity.

The next day, the detectives arrest Karen for the murder of Robert Rasbach. That evening, Brigid goes to see Tom. He is drunk. Brigid tells him she followed Karen the night of the murder. She saw Karen enter the restaurant with the gloves and gun. She heard three gunshots and then saw Karen speed away. Brigid entered the restaurant and found Robert’s body. Brigid tells Tom she will not tell the police what she saw if he has sex with her, and he does.

The detectives get an anonymous tip that the murder weapon is in the Krupp home. They search it and find the gun. Tom confesses to Karen and her lawyer that he had an affair with Brigid. He tells them that Brigid is obsessed with getting him back and that she likely planted the gun in their house. In her next interview, Karen relates the whole story to the detectives. However, she still denies murdering Robert. She insists Brigid was the murderer. She suggests Brigid did it to frame Karen so she could have Tom to herself. The detectives find Brigid’s fingerprints at the murder scene and on the phone used to call in the tip about the weapon. This creates reasonable doubt in Karen’s case, as Brigid could have committed the murder. The district attorney drops the charges against Karen and she is released.

Karen and Tom’s life returns to normal. Karen feels smug that she got away with murder. She thinks about how she planted evidence to make it seem like her late husband, Robert Traynor, was abusive even though he was not. She then stole over $2 million from him, faked her death by suicide, and adopted a new identity. When he called her, she was afraid of her scam being revealed. She had premeditated his murder.

It is revealed that Brigid is pregnant with Tom’s child. Brigid has no intention of giving up on her effort to be with him.