Silver Gravity Books

The Decrypter: Digital Eyes Only - Calla Cress Decrypter Thriller Series, Book 3 (Female-Led Action-Adventure Techno-Thriller)

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Action & adventure, Thriller & suspense, Technology, History, Crime & mystery, Suspense, and Romance

Every Silver Gravity story centres women with agency.

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Facing a foe who blurs reality, she must trust in what she cannot see to expose the truth.

From MI6 secrets to the missing ending of the Bayeux Tapestry, nothing is safe when the Blackhorse Group starts selling history — and Calla Cress is the only one who can stop them.

As tensions rise between nations and the threat of cyber war looms, Calla Cress — a museum curator turned cyber defence agent — is called to the British prime minister’s home to decrypt a mysterious cipher. What looks like a contained security crisis quickly exposes a far deeper threat.

A hi-tech encrypted device containing codes for far-future technologies has been stolen from the NSA’s vault of secrets. Now the perpetrators plan to sell it on the darknet through a shadowy marketplace known only as the Vault — a hidden digital underworld with ties reaching back to the Knights of Malta.

Racing against time alongside NSA agent Nash Shields, Calla is pulled into a lethal game of espionage spanning London, Malta, and Monte Carlo. But the closer she gets to the truth, the clearer it becomes: stopping the sale may require a price she isn’t sure she’s willing to pay.

Action-packed, intelligent, and packed with cryptic puzzles and real-world tech, Digital Eyes Only is perfect for fans of Jason Bourne–style pace, Steve Berry–style mystery, and techno-thriller tension in the vein of The Matrix — with a fierce female lead at the centre of the storm.

If you love modern techno-thrillers woven with coded mysteries, international intrigue, and high-stakes espionage, the Decrypter series delivers.

Reader Praise

"Calla Cress stole my heart—brilliant, brave, and deeply human. I couldn’t put this book down."

"Smart, slick, and seriously addictive. This is the spy thriller I didn’t know I needed."

Listen to the series here:

Locations & interesting places in the novel

Massachusetts Institute of Technology (MIT), USA – The prologue takes place at MIT fifteen years before the main events, involving twin sisters experimenting with dangerous substances.
Chelsea & 10 Downing Street, London – Calla’s apartment and the Prime Minister’s residence. She is summoned to 10 Downing Street to view the encrypted email.
Central London (Whitehall and Westminster) – The story traverses well‑known government districts as Calla interacts with politicians and security services.
Colorado, USA – Calla and her team follow a lead to Castle Rock, Colorado, where a Blackhorse facility is located (from chapter headings and timeline).
Gibraltar – A high‑stakes auction of stolen secrets takes place in Gibraltar, requiring the team to infiltrate a gala and avoid assassins.
Berlin, Germany (Gendarmenmarkt) – The plot takes the characters to Berlin for intel and to track the movement of the “Digital Eyes Only” file (chapter headings).
Munich Residence & Bavarian castle – The climax occurs under a Bavarian castle where the “Digital Eyes Only” server is hidden.
Cape Wrath, Scotland – A coded reference leads Calla to ISTF’s training facility at Cape Wrath, adding maritime suspense (chapter headings).
Caribbean island (Baie Rouge) – Nash waits for Calla in St. Martin, symbolising her desire for a peaceful life. She later returns here to recover after the mission.

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

This book features many of the tropes readers love in female-led action-adventure techno-thrillers, including:

Brilliant heroine under pressure
Codes, ciphers, and cryptography as weapons
Global conspiracy with escalating stakes
Ancient secrets colliding with modern technology
Truth that powerful forces want buried

Book 3 specific:

Stolen NSA vault technology auctioned on the darknet
MI6-level secrecy and a cipher tied to British power
Knights of Malta history threaded into modern espionage

• • Globe-trotting pursuit across London, Malta, and Monte Carlo

Is This Book for You?

This book is ideal if you love:

Female-led techno-thrillers
Action-adventure stories with global settings
Smart heroines who think under pressure
Cryptography, secret histories, and hidden knowledge
Fast-paced thrillers grounded in real-world stakes

You’ll especially love this one if you’re into darknet intrigue, stolen intelligence tech, and conspiracies where history is weaponised.

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.