Shari Lapena’s murder mystery Not a Happy Family (2021) is a psychological thriller about a rich couple who are murdered, leaving their contentious and paranoid grown children as the primary suspects. Much as with Lapena’s seven previous mysteries, Not a Happy Family became an immediate international best-seller, hailed for its deft manipulation of murder mystery elements that recall the intricate architecture of the classic works by Agatha Christie. Other works by Lapena include The Couple Next Door (2016), Someone We Know (2019), and Everyone Here Is Lying (2023).

This study guide uses the 2021 Penguin Books paperback.

Plot Summary

Easter Sunday, the Merton family gathers at the palatial family home for dinner. Fred, a retired corporate executive, and his wife, Sheila, welcome their children: Catherine, the oldest, a dermatologist, and her husband, Ted, a dentist; Dan, who was once heir to the family business but is now unemployed, and his wife, Lisa; and Jenna, the youngest, an aspiring artist and free spirit, and her current boyfriend, Jake.

At dinner, Fred stuns his family by announcing he and Sheila have decided to sell the house because none of the children deserve it. The announcement causes consternation in the siblings, particularly Catherine, who had assumed the house would be hers. Dinner ends abruptly.

Jenna stays after the others depart. Later, it’s revealed that Fred told her he decided to change his will and leave half his money to his sister, Audrey Stancik.

Dan cannot sleep and goes for a long drive to calm his nerves, as is his habit. Catherine decides to return to the house, as her mother wanted to talk to her at dinner but never got the chance. She finds her parents brutally murdered, her mother strangled by an electrical cord, her father stabbed multiple times. Fearing that her brother Dan may be responsible, she decides not to call the police. Before she departs, however, she pilfers her mother’s earrings off her body.

Tuesday morning, the longtime housekeeper, Irena Dabrowski, arrives at her usual time and finds both bodies. Before she calls the police, in an effort to protect the siblings, she cleans off the bloody knife and returns it to the kitchen.

At first the detectives assume, given the ransacked home, that this was a robbery gone bad. But the violence of the killings suggests perhaps this had been an intentional killing. As the investigation unfolds, the detectives discover each family member had a motive. None liked Fred, who emotionally abused them. Fred’s spiteful decision to sell the company six months earlier had left Dan in financial straits. The announcement that they were selling the house disturbed Catherine, and video surveillance reveals to the police that Catherine returned to the house despite telling the police she had not. Then a neighbor reports a mysterious truck decorated with flames that had been in the neighborhood. Nothing adds up.

Audrey reveals to the family that Fred planned to change his will and leave her half of his $26 million estate. The siblings react with rage and disbelief. Audrey believes the money is long overdue to her, as she has kept secret for years that Fred murdered their father. However, lawyers confirm Fred did not have time to actually change the will. The siblings give Audrey the cold shoulder, but Audrey, furious at the loss of her money, conducts her own investigation, determined to find Fred’s killer.

The autopsy reveals that Fred had advanced pancreatic cancer and had only months to live. Then, the family lawyer reveals that Fred had fathered a child by a former employee, Ellen Cutter. That child, Rose, is included in the will. She is now a high-profile attorney who is involved in a massive scheme that defrauded investors out of millions, including Dan.

Dan emerges as the prime suspect. A warrant allows the detectives to find in his garage a box of disposable coveralls, which he claims are from a recent renovation project. The owner of the mysterious truck, a small-time drug dealer, reports to the police that he saw a car in the Merton driveway late Easter night with a vanity plate with Irena’s name. Irena has a solid alibi, however; she points out that all the Merton kids know where she keeps her spare keys.

Police recover a strand of Jenna’s hair in Irena’s car. Jenna dismisses it, saying the hair might have been transferred to Irena when the two hugged at Easter dinner.

Readers then learn what happened Easter night: Jenna, after fighting with her father about the money, plotted to murder her parents. She stole the coveralls, stole Irena’s car, returned to the house, and remorselessly killed her parents. She ransacked the house to make it look like a robbery, then stuffed the evidence in a bag and hid it in the foundation of a friend’s farm building just before a new concrete floor was to be poured. Jenna even poisoned Audrey, putting antifreeze in her iced tea to stop Audrey’s investigation.

But the detectives are stymied. They have no evidence, and the case goes cold. Audrey suspects Jenna and tails her every move. When she sees Jenna stop and chat with the owner of the farm, Audrey herself stops and finds out about the new concrete floor. The police lack evidence to execute a warrant to have the floor dug up. A year goes by. Catherine has a baby, and she and Ted move into the family home. Audrey gets her inheritance, and she notices the farm is for sale. She puts in an offer, presumably to dig up the floor and recover the bag of evidence.