The section-by-section summary is below, but here's the quick version.
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.
Chapters 1 - 5
(A brief prologue introduces two older siblings who are 16 and 14 when a baby joins their family. It also mentions a dark period when some people end up staying with them for over five years.)
The book opens with Libby Louise Jones
inheriting an expensive mansion from the trust of her deceased birth parents (Libby's adopted). At the solicitor's office, Libby learns about her birth parents, Henry and Martina Lamb
, and her two siblings. In the late 1980's, Henry Lamb
inherited his father's money and bought the mansion. Martina is a socialite. But their lives and that of the Lamb's two older kids, a son (also named Henry
) and a daughter, change when the Lambs lose all their money.
A news clipping shows that Henry and Martina were later found dead in the mansion, poisoned in what was presumed to be a suicide pact with one other man (also found dead). The Lamb's two older kids (16 and 14 at the time) went missing. The baby (Libby at 10 months old) was alive. The solicitor takes Libby to the mansion (in Chelsea, at 16 Cheyne Walk), and he gives her a rabbit's foot that was in her crib when she was found. Libby learns her birth name was Serenity
is musician who is living on the streets in France. She was busking for money until her fiddle was damaged. She has two kids (Stella, 5, and Marco
, 12) from separate fathers, and a dog (Fitz
). Stella's father disappeared three years ago. Lucy goes to his mother Samia
(Stella's grandmother who they call Mémé) to ask for help. Samia agrees to takes in Stella for the night. Marco reveals to Libby that he's been in touch with his father and knows where to find him. Lucy gets an alert on her phone that "the baby is 25
(We can piece together that Libby/Serenity is the "baby" who is now 25, and Lucy and Henry (Jr.) are the two older siblings who went missing.)
Chapters 6 - 19
Note: all the parts in the past are flashbacks narrated by Henry Jr. in first person.
In 1988, Birdie Dunlop-Evers
, a semi-famous fiddler, shows up at the Lamb's mansion after Martina invites her to shoot a music video there. Birdie asks to stay for just a few days but soon moves her partner Justin
and cat Suki
in too. Meanwhile, by September 1988, the Lamb family is having financial difficulties. Birdie's friends, the Thomsen family
(David and Sally
and their two kids Clemency and Phineas/"Phin"
), arrive to stay too. David is to be Henry's (Sr.) physiotherapist. Sally will help with home-schooling since the Lambs can no longer afford private school.
At work, Libby contemplates how the house will likely net around 3.5 million pounds after it's sold. She also discovers an article, The Mysterious Case of Serenity Lamb and the Rabbit's Foot
. She learns about the creepy and dilapidated state of the mansion they'd found her in, rumors of a cult and random families living in the mansion. Libby asks her coworker Dido
for advice, and Dido suggests reaching out to the journalist who wrote the article, Miller Roe
. Miller, who worked on the story three years ago, agrees to help investigate.
Lucy and Marco pick up Stella, and they head toward London to find Marco's father (Lucy's physically and emotionally abusive ex-husband), Michael Rimmer
. She reluctantly asks him for money to be able to pick up her fiddle from the repair shop. He gives it to her. That night, Lucy busks and checks them all back into the room they were staying at before to sleep. Lucy also knows its time to return to England to deal with the mansion, and she asks Michael for help to arrange passports.
Chapters 20 - 33
Back in 1989, Henry (Jr.) has a crush on the Thomsen boy, Phin. Martina reveals to Henry (Jr.) that their money ran out a long time ago. Martina is drawn to David Thomasen and thinks he is helping to guide her to a more charitable way of living. Henry (Jr.) soon sees David and Birdie embracing and tells Phineas. Later, Henry (Jr.) and Phin get caught high on acid, and Phin reveals to everyone about David and Birdie's embrace. AS a result, Sally moves out, and Birdie and David start sharing a room. Justin starts teaching Henry (Jr.) about growing drugs.
Present day, in France, Michael arranges the passports, but to get them Lucy needs to go have lunch with him and sleep with him, which she dreads. When things get intimate, Lucy is prepared for it, but when he refuses to stop even after she gets cut by glass, she stabs him. He dies. Lucy cleans up, hoping to leave no trace. She goes home to the kids and bids farewell to her kindly landlord, Giuseppe.
In England, Libby, Dido and Miller got to the house and realize someone else has been in there and on the roof. They wonder if it's one of the siblings. Libby and Miller decide to spend a night in the house. When they hear someone else there, they track them down, and the man identifies himself as Phin.
Chapters 34 - 48
Back in 1990, on Christmas 1990, Henry (Sr.) has a stroke and never fully recovers. David starts issuing very despotic rules for the house. When Phin rebels, David hits him. Phin runs away briefly and when he returns, David is even more controlling. Phin and Henry (Jr.) sneak out one night, and Phin pushes Henry into the river. In anger, Henry runs home and angrily rings the doorbell. Phin is locked in his room for a week. Justin also soon leaves and is never heard from again.
In 1992, Martina announces she is pregnant with David's baby, and Birdie appears to have no objections. David forces everyone to dress the same and confiscates their shoes. With David preening over the pregnancy, Henry tries to sneak natural remedies into his mother's food and drink to terminate the pregnancy. The baby dies.
In the present, Phin introduces himself to Libby and Miller, saying that he's been waiting for her to show up. Phin suggests that they go for a drink to chat. The next morning Libby and Miller awake in a haze and the door is locked. Phin soon comes by and says locking the door was an accident. Libby and Miller also find their phones in the kitchen, which they think is fishy. When a recording Miller made on his phone of their conversation is missing, they suspect Phin drugged them. Miller does some research, leading him and Libby to seek out Sally in Cornwall.
Meanwhile, Lucy and the kids depart France and arrive in London. She takes them to the mansion.
Chapters 49 - 54
After the baby dies, David loses interest in Martina. He soon impregnates Lucy instead. Henry realizes that David wants to use the baby to get the house. Henry (Jr.) uses herbs to put David and Birdie to sleep, and he finds David's stash of cash and his parents' will. Henry (Jr.) recruits Clem in his plan to get out there. (Around this time, Phin is very sick from an unknown disease.)
Present day, at the mansion, Lucy finds "Phin", but she recognizes that it's actually Henry (Jr.).
Libby and Miller find Sally at her office. She politely asks them to leave, and she refuses to let them speak to Clem. Still, Miller manages to use information from her office to track Clem down. When they tell Clem about meeting Phin, she hears their description and informs them they must have met Henry (Jr.). She tells them that Henry is a bit evil, and that he killed Birdie's cat and once tried to drown Phin in a river (as opposed to being pushed, which Henry claims in his narration).
(Note: at this point in the book, it's not clear who's telling the truth and whether Henry Jr. or Clem's version of events is accurate.)
Chapters 55 - 65
Henry Jr. narrates explaining to the reader that he and Phin started pushing each other after Henry tried to kiss Phin. He also explains that he had to test stuff herbs on the cat and the death was an accident. In 1993, the baby (Libby) is born. So, Libby's parents are actually David Thomasen and Lucy.
In preset day, Lucy introduces her kids to their uncle Henry. Henry explains to Lucy that he put a tracking and listening device on Libby's phone. They listen in Libby who is chatting with Clem. Meanwhile, Clem is telling Libby about the night of the deaths. It was the day they were supposed to put the adults to sleep and run away, but the plan went awry. Birdie awoke and Henry attacked her and she died. The other adults died somehow from the sleeping draught, despite Henry's insistence that it was a weak mixture. The kids split up David's stash and Clem runs off to finds her mom.
Henry then messages Libby, showing her Lucy is at the house and they reunite. Lucy and Henry finish telling the story about that night. They say that the next day, when Henry suggests that they go to the police (citing self-defense due to David's molestation of Lucy), but Lucy admits that it is Phin's baby. Lucy then takes Phin to get medical attention (his illness has gone untreated). The doctor takes them in to care for them for a while. When Lucy returns, Henry is gone and the baby has been taken in by the police. Henry ends up taking the name Phineas Thomason, starting a new life and doing well for himself. Lucy says Phin got better but went off on his own eventually, and she doesn't know where he is now. Both Henry and Lucy returned because they knew Serenity/Libby was turning 25. They knew she would inherit and they could see her again.
Chapters 66 - 69
A year later, Libby sells the house for 7,450,000 pounds and decides to split it with Henry and Lucy three ways. Lucy has moved into Henry's flat and gets together regularly with Clem. Henry pays for Marco to attend private school. Libby and Miller become a couple. On her birthday, Miller gives her a brochure to a place he thinks Phin is at, going by the name Finn Thomasen
. He's made a reservation for the two of them.
Henry then narrates admitting that he was the one who gave Phin/Finn the tinctures to make him sick, because he was jealous that Phin didn't love him back. The book ends with him dizzy with the prospect of seeing him again.
See The Family Upstairs