Jenny, Annie’s best friend and a window display designer at Harrods, arrives at Gravesdown Hall from London. After the events of the previous novel, Annie has secured the front door with both the original skeleton-key lock and a modern deadbolt, along with a front-door camera. Jenny finds the house far more unsettling than during Frances’s funeral.

She notices that Annie smells of river water, which Annie traces to the damp tea towel enclosing the ruby-handled knife Archie pulled from the waterwheel that morning. Annie puts the knife in the kitchen sink. They make lunch with items from Archie’s granddaughter Beth, who owns the local deli and makes regular deliveries. They eat in the solarium—a glass Victorian hothouse off the kitchen—while Annie recounts her morning. She voices reluctance about having her fortune told by Peony. Jenny argues that Frances’s fear of her fortune coming true did not ultimately rule her life but turned her into a dedicated mystery solver.

Jenny notices movement in the solarium’s ferns. She investigates and finds Peony Lane’s body, a folded piece of paper in one hand and the ruby-handled knife in her back. Annie recognizes it as the knife she left in the sink less than an hour earlier. They realize this means the killer might be in the house or on the property. They force open the stiff solarium door and escape to the garden. Jenny calls 999.

In her 1967 diary, Frances tells Archie what Eric disclosed about Edmund’s crimes. Archie argues they must investigate whether Ford played any role in covering them up, and Frances points out Ford was only 20 at the time of the crash. Archie also wants to track down Birdy and determine why the accident investigation was suppressed. He reasons that the Gravesdowns bailed Peony Lane out of prison to keep her under their control.

A barmaid makes a pointed remark to Frances about her proximity to Gravesdown money, and Archie explains that local opinion is unlikely to change. Frances agrees to use her access to Ford to gather information but warns Archie plainly: She can see that he is using her, but she will cooperate only while their goals align. If she discovers that he is hiding something or that his own hands are not clean, she will expose him along with everyone else.

In the garden, Annie and Jenny work through the timeline. Since Jenny was facing the ferns throughout lunch and would have noticed any disturbance, they conclude that Peony’s body was already hidden in the solarium before they arrived home, but the knife was placed in her back while they were eating—meaning someone moved through the house while they sat nearby. They discuss access: Beth’s delivery is the only confirmed visit that day, and the gardeners hold keys only to the outbuildings. Jenny raises the possibility of a copied key, while Annie notes the suspicious coincidence of the knife surfacing on Archie’s property that same morning.

Three police cars arrive, led by Chief Inspector Marks. They try the solarium door, which now appears locked. Annie explains that it is simply stiff and describes exactly how to open it, but Marks ignores her and has an officer smash the glass above the handle. When Annie checks the bolt afterward, it is still in the unlocked position—the door would have opened exactly as she said.

Crane arrives carrying coffee and takes their statements. When Annie tells him about her interaction with Peony that morning, he warns her that she has just admitted to being potentially the last person to see Peony alive. When she tells him about the knife, he comments that she has now confessed to recently handling the probable murder weapon. Marks emerges from the solarium with the folded note from Peony’s hand. It reproduces Archie’s fortune, listing the foil, the arrow, the rat, and the sparrow, with the word MINE scrawled across it in red pen. Annie recognizes it but says nothing to Marks. Jenny covertly photographs Crane’s notebook as Marks reads the text aloud.

Marks asks about security. Annie confirms that there are cameras on the front door and the boot-room entrance but not the solarium, where the wiring was too complicated. She makes a mental note to review the footage on her phone as soon as possible. An officer hands Crane a thick file on Peony Lane that he retrieved from inside the house.

As she and Annie are walking around the estate later, Jenny reveals that she traveled to Castle Knoll with Reggie Crane, the local taxi driver, Rowan’s father, a friend of Annie’s mother. Reggie mentioned that Annie’s mother has recently become preoccupied with Peony Lane. More strikingly, Jenny says that when she visited Annie’s mother before leaving London, an elderly woman named Birdy was also there.

In her diary, Frances records the tasks she has assigned Archie—locating the Bentley crash wreckage, obtaining police information (he claims to have an informant), and finding Birdy Sparrow. She writes up a numbered list of questions about Edmund’s crimes, Peony’s alleged brake-cable sabotage, Birdy’s claim to have witnessed a stabbing near the Foyle house and to have seen a ruby-handled knife thrown into the river, and who was actually stabbed.

One night, Archie climbs the tree outside Frances’s window to deliver a photograph of the crash scene smuggled out of the police station by his informant. Tire marks in the photo prove that the brakes were functioning at the time of the crash, meaning Peony could not have caused it by cutting the cable. The marks also curve toward the right despite the road bending left, indicating that the wheel was deliberately turned into the tree.

Frances theorizes that Olivia leaned forward from the backseat and grabbed the wheel—possibly to kill Edmund after learning of his crimes. Scratches around the trunk’s keyhole and the fact that Olivia’s body was found several meters behind the car, in the middle of the road, suggest that she survived the initial impact, tried and failed to open the trunk, then collapsed while attempting to reach help. Archie notes that the complete absence of police inquiry points to a cover-up, and Frances names the obvious beneficiary: Ford. She also tells Archie she has decided to stop seeing Ford, and he offers to accompany her when she tells him.

That evening, Annie discovers that someone has taken the rest of Frances’s files on the Gravesdown family. With the kitchen sealed by police tape, she and Jenny eat pizza by the library fireplace. Frances’s body was found there in the previous novel, and Annie is trying to build better associations with the room.

Crane visits to report a troubling development: The station’s call logs record 11 complaints allegedly made by Annie about harassment from Peony Lane. The calls were all received from Gravesdown Hall’s landline, with a constable named Asha logged as having followed up each time to no answer. Annie counters that she is 25 and would never use a landline; she was unaware the house even had one. She also points out that the repeated unanswered visits only prove someone made the calls while watching to ensure she was out. Crane accepts that she is being framed.

After he leaves, Jenny points out that convincingly passing as Annie on the phone requires a close vocal match, and she names Beth as a strong candidate. Annie suspects, because of the theatrical, elaborate nature of the scheme, that it is the work of Saxon Gravesdown and his wife Elva, who have both motive and intimate knowledge of the house. In the previous novel, Annie had solved Frances’s murder before Saxon and, as a result, inherited the estate; although they are on speaking terms, they are not friendly.

Annie and Jenny walk into Castle Knoll for breakfast along the estate’s woodland trails. They visit a tearoom near the ruins of the original castle, and Jenny is delighted by the adjacent model village and oversized lawn games. Annie gets a motion alert from her front-door camera, but Jenny explains it is a clothing delivery she ordered—outfits with pockets, per Annie’s new resolution to always keep her phone with her. The moment prompts Annie to reflect on how closely her fear-driven habits are beginning to mirror Aunt Frances’s.

Jenny receives a call and needs to leave for Southampton, where her cousin has had a baby, but she promises to return. While they are still in the village, Annie spots Saxon leaving the hardware store with a stack of papers tucked under his arm. She photographs him and zooms in: The label on the file matches Aunt Frances’s filing system, and the name begins with an O. Annie concludes that Saxon has taken Olivia Gravesdown’s file from Frances’s collection, accounting for at least one of the missing files. She identifies Saxon as a strong candidate for the “rat” in Archie’s fortune and decides to visit the police station for backup before confronting him.

In a diary entry, Frances describes going to dinner with Ford at the Castle House Hotel. She plans to end their relationship, and Archie had advised her to choose a public venue. Shortly after they arrive, she spots Archie at a nearby table with an unknown woman with ash-blond hair.

Ford quickly perceives that Frances’s feelings have shifted. When she breaks things off—telling him she dislikes being shut out of so much of who he is—he does not argue. Instead, her candor prompts him to open up and offer his version of events surrounding the crash.

Ford claims that on the night of the accident, Peony Lane arrived at Gravesdown Hall looking for Olivia, who was not home. Ford persuaded Peony that he could be trusted, and she handed him a file on Edmund’s crimes—witness statements, signed affidavits, and sedatives she said she had found in Edmund’s car. Ford says he learned of his brother’s crimes only at that moment and planned to take the file to police himself, but the crash happened before he could act. He says he subsequently delivered the file to the station, but when he followed up the following week, staff had no record of ever receiving it. As for blocking any investigation into the crash itself, Ford admits he did and says he believed it was caused by drunk driving and a marital dispute. He chose to spare his young nephew Saxon the prolonged grief and village gossip. He urges Frances to let the matter rest.