One Dark Summer

ebook / ISBN-13: 9781399725934

Price: £22

ON SALE: 9th July 2026

Genre: Crime & Mystery / Legal Thriller / Suspense

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Lily has spent her whole life not knowing the truth.
Now, one island will change everything.

When she was four years old, Lily’s mother, Penny, walked out the family home and never returned. Growing up, Lily tried to block out the pain of betrayal. But years later, when Lily learns her mum’s family used to own a holiday home on Osea Island, she can’t resist booking a last-minute trip, hoping to finally find a connection to her mother.

But Osea is no ordinary place. Tidal and remote, it keeps its secrets close.

As Lily begins to peel back layers of the past, she uncovers a web of silence, betrayal, and pain stretching back twenty-five years. The island holds the truth of what really happened to Penny and why she never made it back home.

But some secrets aren’t buried in the past. Nor are they still on the island. Some are closer than Lily ever imagined.


Praise for Sarah’s Hornsley’s thrillers:
‘Suspenseful, addictive, twisty’ Fionnuala Kearney
‘Unsettling in the best way’ Roxie Cooper
‘satisfyingly complex, twisty and twisted’ James Oswald
‘A fresh take on a legal thriller’ Amy McCullough
‘Atmospheric with a killer twist’ Catherine Cooper
‘A tangled, twisty thrill-ride’ Cressida McLaughlin
‘A first-rate psychological thriller’ Guy Morpuss

Reviews

PRAISE FOR BAD BLOOD
Incredibly gripping. A triumph
Claire Douglas, bestselling author of THE COUPLE AT NO 9
A tangled, twisty, thrill-ride of a book with a protagonist you won't forget and layers upon layers of secrets and lies
Cressida McLaughlin
A beautifully written, atmospheric thriller with a killer twist - I loved it
Catherine Cooper, Sunday Times bestselling author of THE CHALET
Flawless structure. Taut, intelligent, and shockingly gripping
Will Dean, author of THE CHAMBER
An intricate, clever thriller that delves beautifully into family dynamics and small-town politics. I loved it
Jennie Godfrey, Sunday Times bestselling author of THE LIST OF SUSPICIOUS THINGS
A twisty, gripping, fresh take on a legal thriller . . . Criminally good!
Amy McCulloch, author of BREATHLESS
A satisfyingly complex, twisty and twisted thriller . . . A plot that delights in defying expectations at every turn
James Oswald, author of the Inspector McLean series
Claustrophobic and unsettling in the best way
Roxie Cooper, author of THE DAY WE MET
Suspenseful, addictive, twisty, and yes, it delivers that sucker-punch ending too! I loved it
Fionnuala Kearney, author of THE BOOK OF LOVE
A first-rate psychological thriller!
Guy Morpuss, author of FIVE MINDS
A dark, twisted thriller from a compelling new voice
Russ Thomas, bestselling author of SLEEPING DOGS
Sarah Hornsley's artful writing and lightning-fast plot will leave you breathless and craving more!
Elizabeth McCullough Keenan and Greg Wands, authors of TRUST ISSUES
The head-snapping reveals, jaw-dropping twists, and stunning conclusion make this a masterfully sensational thriller
Samantha M. Bailey, bestselling author of HELLO, JULIET