The Hidden Cipher: A Knights Templar Conspiracy Thriller

by Rich Petrelli

“Gripping”—and Rich Petrelli’s The Hidden Cipher is exactly that… a relentless chase through ancient secrets, modern power, and the shadows between.

When a forbidden Templar manuscript resurfaces after seven centuries, cryptologist Dr. Elena Voss is the first to recognize the symbols etched inside—and the deadly warning buried beneath them. What begins as a routine analysis pulls her into a conspiracy protected by silence, blood, and a hidden order determined to reclaim the cipher at any cost.

Readers of Dan Brown, Steve Berry, James Rollins, Simon Toyne, and Raymond Khoury will feel instantly at home in this pulse-pounding thriller that blends historical mystery with relentless modern danger. The Hidden Cipher explodes out of the gate with breakneck pacing, international intrigue, and a mystery carved into the bones of history.

Joined by covert operative Antoine Rousseau and researcher Liam Hayes, Elena follows a hidden lattice of encrypted symbols across Europe—through echoing cathedrals, forgotten monasteries, restricted archives, and the sealed chambers of Templar strongholds. Each revelation pulls them deeper into a silent war that has smoldered for centuries… and every step forward stirs enemies who have killed to keep this truth buried.

Because the cipher doesn’t just rewrite history—
it reveals a truth powerful enough to end the human race.

In this electrifying, globe-spanning thriller, descend into a world of forgotten orders, encrypted manuscripts, and conspiracies guarded for seven hundred years.
Until now…

412 pages, Kindle Edition

Published December 5, 2025

About the author

Author also write as Color and Quill

Reviews

[Steve Rufle]

Amazing Read.

Really enjoyed the adventures of Elena, Antonio and Liam.

Looking forward to the next book in the Trilogy.

Received as an ARC with no expectation of a positive review.

[Tom Richards · Rating 5 out of 5]

A Gripping Fast Paced Thriller that Pulls Readers In!

A gripping, fast-paced thriller that blends history, mystery, and action in all the right ways. “The Hidden Cipher” pulls readers into a world of ancient secrets, cryptic codes, and relentless pursuit. Dr. Elena Voss is a compelling heroine, and the vivid settings and historical depth rival Dan Brown at his best. A must-read for conspiracy fiction fans!

[Lola Frapp · Rating 5 out of 5]

Dr. Elena Voss discovers an ancient manuscript that contains clues to a powerful secret that she later learns is very dangerous. She travels across Europe with her team to decode symbols hidden in monasteries, fortresses, and crypts. But—her team is being hunted down. This novel is full of mystery and intrigue. A very good read! Looking forward to Book 2!

[Benard Chi · Rating 4 out of 5]

I am enticed with signs and symbols and anything like this book that pivots around it. Elena is my hero and her skills in decoding and interpreting what all eyes take for granted is spellbinding in this captivating thriller. Legacy transfers and preservations is never easy when warring is inevitable.

[Undec · Rating 5 out of 5]

elena voss is smart and real, the codes actually make sense, and the chase scenes kept me up late. history parts felt solid without slowing things down. only gripe is it ends too quick, want the next one already. good thriller if you like smart action.

[Ryan Hillis · Rating 5 out of 5]

A great thriller.