The Family Upstairs by Lisa Jewell, A compelling mystery about a woman who inherits a house with a dark past.
In The Family Upstairs, Libby Jones inherits a multi-million-dollar mansion, where she had once been found as a 10-month-old baby. Along with it, she learns who her birth parents were, but also about their deaths in what investigators deemed to be a suicide pact as well as the two older siblings who went missing.
As Libby looks into the circumstances of their lives, deaths and disappearances, she risks uncovering dark secrets as her investigation leads her down a path of strange discoveries.
Meanwhile, in France, a musician living on the streets realizes that it's time for her to return to London to deal with things she once left behind.
(The Detailed Plot Summary is also available, below)
Detailed Plot SummarySection-by-Section SummarySee the Section-by-Section Summary of The Family UpstairsQuick Plot Summary
In Part I, Libby Louise Jones turn 25 and inherits a London mansion from her birth parent's trust. She learns her birth parents were Henry and Martina Lamb. They died when she was a baby in what appeared to be a suicide pact. Libby' birth name is Serenity. She also had two older siblings (Henry Jr. and Lucy) who mysteriously disappeared. Libby, Miller Roe (a reporter who previously wrote about the story) and Dido (Libby's co-worker), begin to investigate. They find a man named Phin in the mansion.
Meanwhile, in France, Lucy is a musician with two young children, Stella and Marco. Lucy has to ask her abusive ex-husband (Michael Rimmer) for financial help and assistance arranging passports in order to go back to England. However, she ends up stabbing him and killing him after he attacks her. Additionally, via a series of flashbacks narrated by Henry (Jr.), we learn about the Lamb family. Martina allowed a semi-famous musician and her boyfriend (Birdie and Justin) to come live with them, who then invited the Thomasen family (David and Sally, plus their kids Phineas and Clemency) to stay. David began sleeping with Birdie. The Lambs squandered all their money, and David Thomasen began to dictating how everyone in the house lives.
In Part II, Lucy arrives in England. Meanwhile, Libby and Miller hang out with Phin, but suspect that he drugged them. More narration by Henry (Jr.) reveal that Henry (Sr.) eventually had a stroke. Afterwards, David went full-on cult, issuing oppressive rules for everybody. David also impregnated Martina, but Henry (Jr.) snuck herbs in her drinks/food to terminate the pregnancy.
In Part III, we learn that after Martina's miscarriage, David impregnated 13-year-old Lucy, resulting in baby Libby. In present day, Lucy finds Henry at the mansion (masquerading as Phin). (So, Libby and Miller are actually talking to Henry).
Meanwhile, Libby and Miller track down Sally, which leads them to Clem. Clem, Lucy and Henry tell them about that really happened. The kids tried to escape, but Henry's sleeping draught somehow killed all the adults, other than Birdie who awoke and had to be killed. Clem then ran off to find her mom. Afterwards, Lucy admitted to Henry that the baby is Phin's (so, Libby's parents are actually Phin and Lucy) and then took Phin to get medical attention (he's had an untreated illness for a while). The doctor took them in to care for them for a few days, and by the time Lucy returned, Henry was gone and the baby had been taken in by the police (Henry ended up starting a new life and doing well for himself.)
In Part IV, a year has passed. The house sells for 7.45 million pounds, split between Libby, Lucy and Henry. Lucy moves in with Henry, and keeps in touch with Clem. Libby and Miller are dating, and Miller announces that he's tracked down Phin. The book ends with Henry admitting (via narration) that Phin was sick because he was poisoning him (Henry was jealous that Phin didn't love him back), and feeling dizzy with anticipation at the thought of seeing him again.