The Enigma Challenge

by S.C. Godfrey

Genres: Thriller

336 pages, Hardcover

Expected publication August 11, 2026

About the author

SC Godfrey is the author of The Enigma Challenge (2026 from Viking Penguin). She's also the author of A Very Typical Family and The Second Chance Hotel writing under Sierra Godfrey. When not working on books, she can be found reading fast-paced, exciting thrillers, mysteries, and romance. She lives in the Bay Area with her family. Find her at sierragodfrey.com or on Instagram/Threads @sierragodfrey.

Reviews

[Meredith Cox · Rating 4 out of 5]

This book was incredible and so unique. With fast-paced writing, vivid descriptions, and heart-pounding scenes it felt like an actual action movie. From the moment I picked it up I was hooked!

Dr. Zoe Wilder is an American academic cryptologist at a conference in Madrid. After ending things with her boyfriend Eric, she decides to enter the Enigma Challenge. Unfortunately, Zoe has no idea she’s just entered into a game with the highest stakes imaginable. Lose or drop out, and your entire identity will be permanently deleted. Solve the five puzzles and win, and you will receive 12 million dollars.

Dean Seaver, cybersecurity expert and Eric’s enemy number one, realizes the Enigma Challenge has begun and requests they team up. Suddenly, Zoe finds herself in a do-or-die situation as she learns just how far others will go to win. Dane and Zoe decide they must put some trust in one another as they fight to win and stay alive.

This was great from start to finish. I loved the ending and would love it even more if there was a sequel one day!

Thank you to NetGalley and Viking Penguin for providing this ARC in exchange for an honest review.

[☆Laura☆ · Rating 4 out of 5]

Zoe Wilder es una investigadora apasionada por los códigos, que llega a un congreso en Madrid buscando nada más que presentar su trabajo y escapar de su exnovio y controlador jefe. Pero cuando tropieza con una serie de números escondidos en la estatua del Ángel Caído, desata sin saberlo un juego clandestino que nadie admite conocer pero que todos temen: la Enigma Challenge, una competencia donde resolver mal no implica perder puntos, sino perder la propia identidad.


En ese camino aparece Dane Seaver, un experto en seguridad que no solo ha ganado la Enigma Challenge dos veces, sino que también arrastra tantas sombras como habilidades. Lo que comienza como una alianza incómoda se convierte en un dúo obligado a confiar el uno en el otro mientras huyen de jugadores violentos como el 1982, ladrones de pistas, asesinos contratados y, lo peor de todo, ProtoDark, la organización criminal que dirige la competencia desde las sombras.

Mientras Zoe demuestra que su talento supera al de todos los criptólogos profesionales que la subestimaron, también descubre traiciones que la golpean más fuerte que cualquier ataque físico: la revelación de que tanto su excomo Dane estaban involucrados con ProtoDark mucho antes de que ella entrara en juego. Aun así, Zoe avanza, resuelve el último acertijo y enfrenta el dilema final: ganar significa ser reclutada por los mismos criminales que intentaron destruirla; perder significa ser “borrada” del sistema por completo.

Sin más salida que la victoria, Zoe redefine el juego, aprovechando sus propias reglas y convirtiéndose en la única persona capaz de derrotar a un grupo que lleva años reclutando a los mejores. En una competencia diseñada para quebrar a cualquier jugador, Zoe demuestra que los rompecabezas no se ganan por fuerza, sino por claridad, resistencia y la capacidad de ver patrones que los demás pasan por alto.


___


Zoe podrá ser inteligente, pero le falta sentido común.

Thanks to NetGalley, the publisher and the author for the ARC in exchange for an honest opinion.

[Brittany · Rating 5 out of 5]

This book is a genre unto itself—it’s hard for me to put my finger on, but this exactly the type of book I love! It has National Treasure-esque qualities with the puzzles and cryptology and fast-paced adventure feel. I have so many compliments—fantastic title, engrossing premise, compelling characters, and incredible European setting!

Plot: Dr. Zoe Wilder is technically in Madrid for a cryptology conference—off the record, she’s there to participate in the notorious Enigma Challenge. With no idea of what the contest entails, she relies on adrenaline and newfound ally, Dane Seaver, to get her through the five puzzles that lie ahead. Luckily, puzzles and ciphers are Zoe’s thing. As she and Dane traipse across Europe solving each stage of the challenge, they start to build a rapport beyond just working well together. More than just puzzles stand in the way of the multi-million dollar prize—there are players who are out for literal blood. Oh and of course another incentive to win is avoiding identity deletion—the fate of all other players. Worth playing for? I’d say so.

Y’all—the only bad thing about this book is that it’s not being published until August 2026! But put it on your list now! This is one of the best books I’ve read this year and if I had the power to do so, I’d demand a sequel! We the readers need more Zoe & Dane! More action, more everything pretty please! I will be thinking about The Enigma Challenge for a while and am so impressed by Godfrey’s writing. This book was captivating from cover to cover—chef’s kiss in every way!

Thank you so much to Viking Penguin, S.C. Godfrey, and NetGalley for the ARC of The Enigma Challenge

[Andi · Rating 5 out of 5]

4.5 stars. THE ENIGMA CHALLENGE was an outstanding debut that caught me completely by surprise. The pacing started fast, and never slowed.

Zoe Wilder is an academic cryptologist who is in Madrid to speak at a conference with her boss/former boyfriend. An expert in ciphers, she unwittingly solves a puzzle to kick off the “Enigma Challenge,” run by a secret group. The challenge involves a set of five puzzles and multiple locations, with one winner and a twelve-million-dollar prize. What she doesn’t realize before playing the game is that all losers will have their identities deleted , including their social security numbers, bank accounts, credentials, etc. Yikes!

Lucky for her, Zoe has a photographic memory that aids her in the cipher challenge. She reluctantly partners with Dane Seaver, who has a bit more insight into the challenge than Zoe.

The plot kept me interested, although I had no clue how to solve any of the ciphers. And the ending was fantastic. I hope the author decides to make this into a series!

🌟Thanks to the author, publisher, and NetGalley for a copy of this book in exchange for an honest review.🌟

[Natalie K · Rating 5 out of 5]

Zoe Wilder, an academic cryptologist (I didn't know that was a thing and it's fascinating) goes to a conference in Madrid, where she unexpectedly dumps her mediocre boyfriend and enters a terrifying puzzle contest called the Enigma Challenge. Run by a mysterious hacking group, the prize is twelve million dollars. The catch? Everyone who loses gets "deleted" off the internet and databases, meaning your social security number isn't valid anymore, so you can't open a bank account, get a job and get paid, etc.

Zoe teams up with Hot Cryptographer Dude named Dane and together, they travel around Europe solving the puzzles. They get themselves into a few hairy situations, as their fellow competitors will stop at nothing, including breaking bones and literal murder, to ensure a win. Though I think some of this was a bit fantastical (does any one group actually have access to enough databases around the world to be able to "delete" people?), it was an extremely fun ride overall. Highly recommended!!!

Thank you to NetGalley for the free copy!

[MichelleZ · Rating 5 out of 5]

This incredible book started off with a bang and just kept on going! I'm posting this review at 2 in the morning because I could not put it down. I read it during work (shhh...) and right through the night.

It starts off in Madrid, where Dr Zoe Wilder gets rid of her man/boss and enters the contest of her life. Who knew solving ciphers, which are Zoe's expertise, and puzzles could win millons? At the same time, it could cost her life. She teams up with Dane Seaver, who is easy on the eyes, and travels through Europe to try and win the Enigma Challenge.

One of my favorite parts about this book was looking up places they went to and seeing the beautiful things they saw. It put me right there with them as they traveled.

I highly recommend The Enigma Challenge and I'm hoping for a sequel!!!

Thank you big time to Viking Penguin, S.C. Godfrey and NetGalley for the ARC of The Enigma Challenge

[Caroline · Rating 5 out of 5]

I had so much fun with The Enigma Challenge. It’s perfect for grown fans of The 39 Clues series, the amazing race and national treasure. The plot kicks off right away and never slows down, and I loved how the mystery kept expanding in ways that actually surprised me. The characters were great and had fantastic chemistry.

This is one of those books where you think you’ll read a chapter before bed and suddenly it’s way later than it should be. If you like high stakes, clever twists, and an easy to fall into reading experience, this one deserves a spot on your shelf. I’m already tempted to reread it, especially if we get a sequel! Definitely one of top reads for 2025!

Thank you to NetGalley for the ARC.

[Rodney Booe · Rating 4 out of 5]

The Enigma Challenge was a thrilling ride from start to finish. The characters were well developed. The plot moved along quickly. Zoe was immediately likable, but I never knew who could be trusted to the end. I finished the book thinking that I was a cryptology expert. In all seriousness, one doesn't have to love puzzles and codes to enjoy this book. I hope there's a sequel in the works. It was set up beautifully for a potential sequel, but even without it, The Enigma Challenge was a worthwhile read.

I was given an advance copy to review.

[Dena Schulze · Rating 4 out of 5]

The pacing of this book was very fast and exciting. Similar vibes to National Treasure or the DaVinci Code. I thought the romance happened a little too fast but I guess that’s what happens when you are running for your lives! A very enjoyable read.