Sadie is forced to take extended leave from the Met after leaking information to the press about the mishandled Bailey case.

During a run near her grandfather's home, Sadie stumbles upon an overgrown, long-abandoned lake house hidden in the Cornwall woods.

Neighbor Louise tells Sadie the abandoned estate is Loeanneth, where the Edevane family's baby boy Theo disappeared without a trace.

At the local library, Sadie spots an advertisement for A.C. Edevane's novels and connects the author's name to the abandoned estate.

Alice receives a letter from Detective Sadie Sparrow asking about Loeanneth and tells Peter the detective has confused her with someone else.

Eleanor deShiel is nearly struck by a London bus and is saved by a young medical student named Anthony Edevane.

Anthony's parents and siblings all die when the Titanic sinks, leaving him the sole heir to his family's enormous fortune.

Anthony uses his unexpected inheritance to purchase Loeanneth, restoring Eleanor's beloved family estate in Cornwall.

Anthony returns from World War I with severe shell shock, making daily life at Loeanneth increasingly frightening and unstable.

Eleanor begins a secret love affair with Benjamin Munro and discovers she is pregnant with his child.

Searching Eleanor's private letters at Loeanneth, Sadie and Clive discover that Theo was Ben Munro's son, not Anthony's.

Alice and Peter arrive unexpectedly at Loeanneth to search for answers, and Sadie's grandfather Bertie also appears at the estate.

Sadie lays out everything she has pieced together about Eleanor's plan to have Ben secretly remove Theo from the nursery.

Bertie recognizes Eleanor's face in an old newspaper photograph and shares childhood memories of his Uncle Ben and a plush toy dog.

When Bertie's toy dog is missing the same button Sadie found on the nursery floor, Alice realizes Bertie is her brother Theo.

Sadie Sparrow, a London detective forced onto leave after leaking information to the press, stumbles upon the abandoned Edevane estate in Cornwall and becomes consumed by the cold case of baby Theo's disappearance. As she investigates, the story of the Edevane family unfolds: Eleanor and Anthony's whirlwind romance, their inheritance of Loeanneth, and Anthony's devastating psychological damage after World War I. Eleanor's secret affair with gardener Ben Munro results in Theo's birth, and when Anthony's condition worsens to a dangerous degree, Eleanor arranges for Ben to secretly remove Theo to safety. Decades later, Sadie uncovers the truth hidden in Eleanor's private letters and solves a mystery that has haunted the family for seventy years. The investigation culminates in a stunning reunion when the group realizes that Sadie's own grandfather Bertie is the missing child Theo, restoring the Edevane siblings to one another at last.

The central mystery of Theo Edevane's disappearance, solved across two timelines.

In the dead of night, a woman buries a box in the Loeanneth woods and is overwhelmed by remorse over what she has done.

Howard Mann visits Loeanneth before the war, and he and Eleanor discuss Anthony's determination to enlist and the dangers that lie ahead.

Clemmie takes baby Theo from his crib in the early hours of Midsummer's Eve morning and carries him to the lake to skip stones.

Sadie meets retired detective Clive Robinson and learns that Daffyd Llewellyn died by apparent suicide shortly after Theo's disappearance.

Alice meets her sister Deborah for their annual tea and carefully steers the conversation toward the night Theo disappeared.

Deborah leaves a message for Alice through Peter confirming that she does, in fact, remember the man named Benjamin Munro.

Sadie interviews Nanny Rose's great-niece Dr. Margot Sinclair and discovers that Rose's secret child was a daughter, not a son.

Anthony suffers a violent flashback episode in the garden and tries to strangle the family dog Edwina while his daughters watch in terror.

Nancy Bailey visits Sadie's flat and shares her daughter Maggie's notebook, which records a dinner date with a man called MT.

Eleanor recognizes the young man from her train journey when she collides with him outside the Cornwall post office.

Eleanor accepts Ben Munro's invitation into his Gypsy wagon during a sudden rainstorm while searching the grounds for her runaway dog.

Anthony secretly steals supplies from the commissary and helps Howard plan a late-night escape from a barn with Sophie and her son.

Howard is executed for desertion after telling the arresting officer that Anthony had been trying to stop him all along.

Sadie calls the Met superintendent, confesses to being the press leak, and threatens to go public again if her new lead is ignored.

Eleanor enters Flo's London shop during the war and quietly talks with a young boy she instantly recognizes as Theo.

From the ominous nighttime burial of a box in the Loeanneth woods to Eleanor's first fateful encounters with Ben Munro, this pool traces the secondary events that gave the central mystery its shape. Anthony's best friend Howard visits Loeanneth before the war, setting the stage for a devastating desertion attempt that will scar Anthony for life, while Eleanor's chance meetings with Ben plant the seeds of an affair that will change everything. As Sadie pursues the cold case in 2003, she meets key witnesses, dismantles her early theories about Nanny Rose, and brings the Bailey investigation to its harrowing resolution. The pool also captures how mothers fight relentlessly for their children: Nanny Rose, Nancy Bailey, and ultimately Eleanor herself, who makes an unthinkable sacrifice to protect her son. It closes with Eleanor's secret wartime visit to a young boy in a London shop — the closest she will ever come to holding Theo again.

The supporting events that shaped the Edevane tragedy and Sadie's parallel investigation.

Alice agrees to meet Mr. Llewellyn at half past eleven that night while waiting by the lake for Ben during party preparations.

Eleanor and Anthony marry, and despite her reservations, Eleanor allows her cold and embittered mother Constance to live with them at Loeanneth.

Anthony leaves for France as war breaks out, parting from Eleanor and their young daughter while Eleanor is pregnant with Alice.

Sadie discovers an old love letter written by Eleanor inside the abandoned Loeanneth boathouse, intensifying her curiosity about the cold case.

Sadie wakes from a restless night and calculates that Nanny Rose's recorded absence perfectly matches the period around Theo's birth.

A near-accident with a gin bottle interrupts Clemmie just before she can tell Alice what she witnessed in the Loeanneth boathouse.

Peter discovers that multiple pages have been torn from Alice's old notebooks and that the initials BM appear repeatedly throughout.

Alice arrives at Deborah's house braced to confess her belief that she caused Theo's disappearance through her friendship with Ben.

Before Alice can speak, Deborah interrupts and declares that what happened to Theo was entirely her own fault.

During their tense first meeting, Alice reveals to Sadie that Eleanor had a secret love affair with gardener Benjamin Munro.

Alone in the Loeanneth woods, Anthony relives the night he tried to silence Sophie's infant son to protect Howard's escape from camp.

Eleanor watches Anthony's condition deteriorate dangerously after Theo's birth and resolves to have Ben secretly remove the baby to safety.

Constance invites Daffyd Llewellyn to share champagne at the Midsummer party and secretly poisons him with barbiturates during their conversation.

Ben coldly rejects Alice's declaration of love at the boathouse, and a humiliated Alice storms off alone into the Midsummer woods.

Alice directs Peter to dig up a buried box in the Loeanneth woods, unearthing her very first manuscript from seventy years earlier.

This pool traces the pivotal moments of decision and revelation that drive the novel's mystery to its conclusion. From Alice's fateful agreement to meet Llewellyn on Midsummer's Eve to the gradual unraveling of what truly happened that night, each event marks a point of no return for the characters involved. Sadie's detective work surfaces clue after clue — Eleanor's love letter in the boathouse, a pattern of torn notebook pages, an impossible match of dates — while Alice is forced by her sister Deborah to confront a truth she has suppressed for decades. The pool illuminates the Midsummer's Eve party in devastating detail: Constance's cold-blooded poisoning of Daffyd, Alice's heartbreak at the boathouse, and Eleanor's agonizing farewell to her son. It closes with the recovery of Alice's buried manuscript, a final artifact that bridges the past and the present and confirms the shape of a secret kept for seventy years.