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Silver Gravity Books

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The Decrypter: The Falcon Syndrome: Rose Sandy, Calla Cress Decrypter Thriller Series, Book 9

Suspense, Thriller & suspense, Action & adventure, and Crime & mystery

Every Silver Gravity story centres women with agency.

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Ancient codes. Modern science. The secret to eternal life.

In the shadowy world where codebreakers reign supreme, one ancient diary threatens to rewrite the laws of human mortality, and everyone is willing to kill for it.

When brilliant ISTF codebreaker Calla Cress receives a cryptic message about a mysterious Renaissance diary, she is thrust into a high-stakes race against a ruthless adversary. The diary contains more than history. It holds the genetic blueprint for immortality, created by a secret society of chemists centuries ahead of their time.

As Calla and her elite team peel back the diary's layers of impossible codes, corporate titan Kenzel mobilises his vast resources to seize its secrets. With his son's life hanging in the balance, his desperation makes him the most dangerous kind of enemy, one with nothing to lose. When Kenzel kidnaps renowned geneticist Dr. Elizabeth Smith to unlock the diary's final secrets, Calla isn't just chasing codes. She's hunting a predator while protecting knowledge that could transform or destroy humanity.

Locations in This Book

Zurich, Switzerland - A peace conference where global leaders begin to behave erratically after a covert neural attack
Jerusalem, Israel - Home to the Falcon Scrolls, hidden beneath catacombs and guarded by an ancient order
British Library, London - A digitised manuscript reveals truths about memory corruption and AI evolution
Doha, Qatar - A data hub for neurological warfare where FALCON's code takes shape
Oxford, UK - Academic cover-ups and a neuro-lab hold secrets from Calla's past
Tel Aviv, Israel - A covert facility reveals the link between the ancient scroll and the modern mind weapon

Reader Praise

"A visionary thriller that makes you question what's real and what's programmed."
"Fast-paced, intelligent, and frighteningly plausible."
"Calla Cress faces her most psychological and personal mission yet."
"Mind-blowing twists and jaw-dropping science, this one lingers long after the last page."

Perfect for fans of Steve Berry, Scott Mariani, Ernest Dempsey, and Clive Cussler who demand smart, sophisticated adrenaline.

About the Calla Cress Decrypter Series

The Calla Cress Decrypter Series is a female-led action-adventure techno-thriller series that blends global espionage, cryptography, and high-stakes discovery.

Often compared to a female James Bond crossed with Indiana Jones, the series follows Calla Cress, a brilliant cryptographer and museum curator whose expertise in ancient manuscripts and hidden systems draws her into international conspiracies. As intelligence agencies, criminal networks, and secret organisations collide, Calla is forced to navigate a world where knowledge is power — and decoding the truth can destabilise nations.

Each book stands alone while contributing to a larger arc of global intrigue, making the series perfect for readers who enjoy smart, fast-paced thrillers led by a woman who survives on intellect, courage, and moral clarity rather than brute force alone.

What Kind of Thriller Is This?

This book is best described as a female-led action-adventure techno-thriller.

It combines:

Technothriller elements (cryptography, data, hidden systems, modern intelligence warfare)
Espionage and conspiracy involving governments and shadow organisations
Action-adventure storytelling across global locations
A smart female protagonist whose intelligence drives the plot

If you enjoy thrillers where ideas are as dangerous as weapons — and where discovery triggers global consequences — this series is designed for you.

If You Love James Bond or Indiana Jones…

Readers often compare this series to James Bond and Indiana Jones, but with a modern, female-led twist.

Like James Bond, the story features global stakes, intelligence agencies, and dangerous conspiracies.
Like Indiana Jones, it revolves around ancient knowledge, hidden artefacts, and discoveries that reshape history.

What sets Calla Cress apart is that intelligence is the primary weapon. Codes replace gadgets. Pattern recognition replaces brute force. And the heroine’s strength lies in insight, scepticism, and resolve.

Story Tropes & Reader Appeal

Is This Book for You?

Do I Need to Read the Series in Order?

Each Calla Cress novel is written to stand alone, with its own central mystery and resolution.

However, reading the series in order allows you to follow Calla’s evolving relationships, growing influence, and the wider conspiracy arc that unfolds across the books. New readers can start here, while returning readers will uncover deeper connections.

The Calla Cress Decrypter Thriller Series In Order

Book 1: Secret of the Lost Manuscript
Book 2: The Mind Hacker
Book 3: Digital Eyes Only
Book 4: The Storm’s Eye
Book 5: The Pythagoras Clause
Book 6: The Beale Ciphers
Book 7: Atlantis of the Sands
Book 8: Kingdom of Diamonds
Book 9: The Falcom Syndrome
Book 10: The Queen of Sheba
Book 11: The Calculus Warning
Book 12: The Cobra Paradox
Book 13: Room of Martyrs
Book 14: Eiger Mosaic
Book 15: Enemy of Wolves
Book 16: The Pharaoh's Mask
Book 17: The Eternity Hypothesis
Book 18: The Sculptor's Code
Book 19: The Solomon Agenda
Book 20: The Pheonix Cipher
Book 21: The Cairo Key
Book 22: Red Fox Agenda
Book 23: Phaistos Disc
Book 24: Scorpion Gold

About Rose Sandy

Rose Sandy is an independent author and publisher known for writing female-led action-adventure and techno-thriller fiction.

She is the creator of the Calla Cress Decrypter Series, a globe-spanning techno-thriller series often compared to a female James Bond crossed with Indiana Jones. Her work blends cryptography, global conspiracy, and high-stakes discovery, with a focus on intelligent heroines who survive through insight, courage, and moral clarity.

Rose Sandy’s stories are characterised by fast-paced plots, international settings, and the collision of history, technology, and power. Her fiction is written for readers who enjoy smart thrillers with real-world stakes and strong female protagonists at the centre of the action.