Mark is fired from his banking job after his boss discovers he was planning to switch companies.

Mark and Erin decide to take a honeymoon in Bora Bora as their last extravagant trip before cutting back on spending.

Mark and Erin find a locked duffle bag floating in the ocean while returning from a scuba session.

Mark and Erin scuba dive back to the site and discover a crashed plane containing five dead bodies inside.

Erin secretly powers on the iPhone from the bag and accidentally alerts an unknown person that the phone is active.

Erin erases hotel security footage by faking food poisoning, then Mark deletes their guest information from the hotel computer.

Mark and Erin successfully smuggle the money, diamonds, and USB drive through airport customs and back to England.

Mark and Erin fly to Switzerland and deposit the stolen cash into an anonymous shell bank account.

Mark and Erin learn that a couple who stayed at their Bora Bora hotel died in a suspicious scuba diving accident.

Erin interviews Eddie Bishop at Penton Prison and agrees to sell the stolen diamonds through his criminal contacts.

Eddie's contact collects the diamonds and sells them, depositing two million into Erin's account.

Erin turns on the bag's iPhone and discovers a voicemail offering money for the USB that Mark has secretly already heard.

Erin watches from hiding as Mark hands the USB drive to an armed man in a deal arranged entirely behind her back.

The armed man shoots Mark dead after Mark fails to provide the coordinates of the downed plane.

Erin buries Mark's body, plants a false trail of his movements, and reports him missing to the police.

Something in the Water begins with Erin and Mark's comfortable life upended by Mark's sudden firing from his banking job. Their honeymoon in Bora Bora takes a dark turn when the couple discovers a duffle bag filled with stolen money, diamonds, and a USB drive pulled from a crashed plane carrying five dead bodies. Acting to cover their tracks, they erase hotel records and smuggle the contents home, drawing themselves deeper into criminal behavior. Back in England, they launder the money through a Swiss bank account and attempt to sell the diamonds while learning that an innocent couple from their hotel has died under suspicious circumstances. Growing evidence that someone is still looking for the bag leads Erin to turn on the bag's hidden iPhone, where she discovers Mark has been secretly listening to a voicemail offering payment for the USB. In a devastating confrontation in the Norfolk woods, Erin watches Mark betray her to an armed buyer, who shoots Mark dead, forcing Erin to bury the evidence and report her husband missing.

The core thriller plot from job loss to murder.

Erin interviews Holli Byford at Holloway Prison and finds her clearly unrepentant about setting a bus on fire during the London Riots.

Mark erupts during a wedding food tasting, insisting they should cancel the wedding and sell their house to survive.

Erin interviews Alexa Fuller at Holloway Prison, whose quiet hope of having a baby after release deeply resonates with Erin.

Erin overcomes her fear and scuba dives with Mark for the first time since a traumatic past experience left her terrified.

A bottle of wine sent by Eddie Bishop arrives at the Bora Bora hotel room, unsettling Erin who wonders how he knew her location.

Mark and Erin get drunk and try to cut the duffle bag open with scissors, barely making a mark before falling asleep.

Erin uses a sharp knife to fully open the bag, revealing cash bundles, loose diamonds, a gun, and a USB drive.

Mark and Erin research the downed plane and identify it as registered to a Russian shell company called Aegys-Mutual Consultants.

Mark and Erin decide to keep the bag's contents, concluding that no one with illegal ties would publicly come looking for them.

Erin discovers she is pregnant while hiding the money and diamonds in the attic after returning from Bora Bora.

Erin meets Detective Andy Foster during Holli's follow-up interview, learning Holli has vanished and Erin herself may be under investigation.

A man calling himself Patrick stops Erin outside Penton Prison, but the prison has no record of any employee by that name.

Erin arrives home to find the back door open, a photo of her and Mark missing, and strange messages on the answering machine.

Erin meets Eddie's estranged daughter Lottie, who firmly refuses to let her father back into her life despite a recorded message from him.

Erin and Alexa spend Christmas together, and a breaking news report shows Holli committing a robbery somewhere in London.

This pool follows the secondary beats that shape Erin's world before and after the bag is found. Through her documentary work, Erin interviews Holli, Alexa, and Eddie — three convicts whose attitudes toward crime and freedom quietly foreshadow her own descent into illegal activity. Mark's emotional unraveling becomes starkly visible at the wedding food tasting, while Erin's discovery of her pregnancy raises the stakes of every dangerous choice she and Mark make. The investigation into Holli's disappearance brings Detective Andy into Erin's orbit, and a mysterious man named Patrick outside the prison and a broken-into home make clear that someone is closing in. After selling the diamonds through Eddie's underground connections, Erin cautiously pieces together that the world around her is far more dangerous than she admitted. The novel closes with Erin and Alexa rebuilding their lives side by side, watching Holli appear on a breaking news broadcast — a quiet reminder that some people never change.

The characters and secrets that fill out the story.

Mark and Erin celebrate the anniversary of their first meeting, and Mark admits growing dissatisfaction with his demanding banking career.

Eddie Bishop calls Erin from prison and reveals he knows details about her upcoming wedding, suggesting she has been investigated.

Mark and Erin get married and fly first class to Bora Bora for their honeymoon, with Erin feeling a rare sense of total freedom.

A tropical storm hits Bora Bora and forces Mark and Erin to use a different beach location for their next scuba dive.

Mark and Erin hand the duffle bag in to the hotel staff but later find it sitting at the foot of their bed.

Erin panics near the downed plane and returns to the surface, leaving Mark to explore the inside of the crashed aircraft alone.

Mark admits he told hotel staff the bag belonged to the Sharpes in a moment of panic, explaining why the couple was targeted.

Erin visits a diamond exchange on her own initiative and successfully sells a stone, confirming all the stolen gems can be moved.

Mark confronts Erin after finding Detective Andy's business card in her coat and admitting he read through her private emails.

Erin films Alexa's release from prison and their relationship shifts from a professional arrangement to a genuine personal friendship.

Erin finds the missing USB drive hidden inside a box of truffles, realizing Mark deliberately concealed it from her.

Eddie gives Erin a gun for protection and Erin sends a message arranging to exchange the USB drive for two million euros.

Erin drives to Norfolk a day early to scout the trade location and buries the USB to control how the exchange will unfold.

Patrick breaks into Erin's hotel room and attacks her; she regains consciousness locked inside the bathroom with a bloody head wound.

Erin searches Mark and Patrick's burner phones and discovers Mark secretly hired Patrick to manipulate and terrify her from the very beginning.

This pool traces the key decisions and shocking revelations that define the novel's emotional arc. From the moment Eddie's unsettling phone call hints that Erin is being watched, warning signs about the people around her begin to quietly accumulate. Seemingly small moments — a storm that forces a route change, a bag that reappears in the hotel room, Erin surfacing alone while Mark explores the plane — carry enormous consequence for everything that follows. Mark's betrayal reveals itself in layers, from hiding the USB inside a box of truffles to confronting Erin about her secrets while concealing far larger ones of his own. The exchange arranged in Norfolk brings everything into terrifying focus: Patrick's attack in the hotel room, Erin's realization of Mark's true plan, and the gunshot that ends his life. The pool closes with Erin searching the burner phones and finally understanding the full scope of how Mark orchestrated her fear and set her up to take the fall from the very beginning.