The Enigma Challenge

by S.C. Godfrey

You have solved the kickoff puzzle. There will be five additional puzzles to solve. Players have five minutes to confirm PIN after locating the final solution. The Enigma Challenge begins now.

An action-packed novel following an unlikely duo as they race across Europe in a dangerously high-stakes competition worth millions

Zoe Wilder has the unflashy, solitary life of an academic, studying ciphers in literature at a California university. When her research takes her to a cryptology conference in Madrid, she's not expecting to kick off the Enigma Challenge, a clandestine puzzle competition few dare to enter.

The Enigma Challenge is an infamous competition with impossibly high lose, and your identity is wiped forever. It doesn't take long for Zoe to realize that she's in over her head. Enter Dane the mysterious hacker who insists they team up. Dane knows the Enigma Challenge—its secrets, its players—and Zoe knows ciphers. For better or worse, they need each other. 

Six days, five puzzles, three countries, and innumerable rivals. What's more, the spark of attraction between them becomes harder to ignore, but distractions are dangerous. With twelve million dollars and multiple lives on the line, the Enigma Challenge is anyone's game. Will Zoe and Dane come out unscathed against the other players—and each other?

Genres: Thriller, Mystery, Romance, Fiction

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 · 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.

[Jill Elizabeth · Rating 4 out of 5]

I wasn't sure about this one for a while, but I'm glad I stuck with it because it wound up being fun (if a little repetitive in its relentless pursuit of the mystery). It's over the top, sure - but in a (mostly) good way, like a blockbuster movie. If you expect to not only suspend disbelief but throw the whole concept of it out the window early on, you'll find yourself on a wild ride that moves quickly and shuffles you about in zany ways.

The characters, plot, and pacing are all presented in an oversaturated technicolor bonanza of details that are engaging - and nerve-wracking. I did find some of the early back-and-forth with the puzzles to feel repetitive, but things smoothed out as the Challenge progressed, and from there to the end was a manic flurry of activity that I found quite entertaining. The last half definitely brought this solidly into four-star territory for me.

Thanks to NetGalley and the publisher for my obligation-free review copy.

[Sandy · Rating 5 out of 5]

A great book featuring main character Dr. Zoe Wilder who is a cryptologist from the San Francisco Bay area. She has traveled to Madrid to present a paper with the support of her boss and significant other, Eric. Zoe has a bigger objective: to play in the annual Enigma Challenge. Little does Zoey know how high the stakes are for losing.

The first clue brings Zoey to a famous statue in Madrid where she finds not only an encrypted clue to be solved but also Dane Seaver. Dane is heavily involved in cyber security. and is Eric's archnemesisis. He may either prove Zoeys knight in shining armor or her ticket to "being deleted".

As Zoey continues to solve clues, most of the time being in grave danger, she waves her way through European capital cities. I

I love the depth the author writes in to her characters. The descriptive way she writes about the locations of the clues, the chases, and even scenes between characters makes the reader feel as if they are present sometimes almost painfully so.

S. C. Godfrey has written books before under her given first name. I'm thinking the move toward the change is because of the change in the genre? Im following the author now as I'd love to hear all about her research on some of the aspects of this well-written novel.

Highly recommend. One of my few 5 stars this year.

This ARC was provided by NetGalley and VikingPenguin in exchange for an honest review.

[sydney · Rating 5 out of 5]

i did not want to get off this rollercoaster ride of a book! it is action packed from the start. this reminds me of The Amazing Race but from a cryptography perspective.

i enjoyed the buildup of the romance between the main characters. all i got to say is poor Zoe, she went through the ringer in this book :(
the found family element is so sweet and added emotional depth to the plot.

the cliffhanger should be a crime, i need the next book now!

Thank you NetGalley and Viking Penguin for the eARC.

[Gabrielle D'Alessandro · Rating 5 out of 5]

oh my gosh. we need a part ii immediately pls 😊😅🥹

[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

[Lizz · Rating 4 out of 5]

The Enigma Challenge is fast-paced, engaging, and really well written. The challenges themselves were complex, but they were explained clearly enough that they were easy to follow—and they actually made me curious about learning and messing around with ciphers myself. I also liked how much the story moved around; even with all the location changes, each place felt vivid and easy to picture. The interactions between the main characters and side characters felt natural and believable, which made the whole story even more enjoyable to read.

I flew through this book way faster than I expected because it was so action packed. I look forward to the next book!

Thank you NetGalley and Viking Penguin for the ARC in exchange for an honest review.

[grey ☽ · Rating 5 out of 5]

ARC review! 5 stars

I couldn't put this down. The plot was so unique and the FMC and MMC had amazing chemistry. I thought the spice was just the perfect amount. I really felt like I was in Europe, especially Spain. The ending had me absolutely screaming and I really hope we are getting a second book! I definitely recommend this to anyone who likes The Amazing Race & the puzzles and riddles in Survivor. Loved it!

Oh, and this line will live in my head forever, rent free.

"I haven't stopped thinking about them." -Dane
🥵🔥

Thank you Victory Editing for this arc!

[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.

[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.

[Michelle · Rating 5 out of 5]

You have solved the kickoff puzzle.

The Enigma Challenge begins now.

Zoe is a cryptologist... leading a rather normal, unassuming... boring life as a cryptologist studying ciphers in literature at a California university. That is until her research leads her to a cryptology conference in Madrid, Spain...and she finds herself involved in a dangerous competition with stakes that are far too high...and if you lose? Your identity is gone forever.

It doesn't take long for her to realize that she is in far over her head. That's when a mysterious hacker makes his appearance... Enter Dane Seaver... who knows the Challenge's secrets and its players. Regardless of how this ends up... for better or for worse, they need each other.

Twelve million dollars lies at stake. Six days. Five puzzles. Three countries.

Multiple lives at risk.

Will Zoe and Dane make it through the Challenge unscathed? Even more important... will their growing feelings for each other grow more... or will they be shattered apart?

Allow me to tell you now, grab on to something, and hold onto it tight... because you are absolutely not prepared for the wild ride that The Enigma Challenge will take you on. This starts off with a bang, and then descends into a rapidly dropping, utterly thrilling rollercoaster of a ride... one that I found so utterly thrilling that I just kept reading and reading until I was finished with it at 3 am in the morning.

And oh my stars, can S.C. Godfrey write. The scenery! She writes in such a vivid fashion that the whole novel seems to spring to life... and throughout the whole thing I almost felt as though I was experiencing the cities for myself... the sights, the smells, and the landmarks that each of these cities is known for...even though I have only managed to visit one or two of them myself. She then uses this same vivid imagery and wraps it into a masterful, heart-racing tale of puzzles, symbols, and ciphers... where danger lurks around every corner... all at the same time, we have a blossoming relationship as our two main characters get to know each other.

There is plenty here that will keep you engaged, and there is also plenty more that will leave you yearning to know more about the Challenge, about its puzzles, and all-in-all, the ultimate winner of the prize. S.C. Godfrey's writing is always a delight, and I cannot wait to see what she releases next.

Thank you to Pamela Dorman Books, Viking Penguin, and Netgalley for the opportunity to read this in advanced! All thoughts and opinions are my own and the rest of my reviews may be found at: https://littlereapling.wixsite.com/fa....

[☆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.

[Lauren · Rating 4 out of 5]

I received an advanced copy of The Enigma Challenge by S.C. Godfrey from NetGalley and Pamela Dorman Books/Viking in exchange for an honest review. I knew this book would be a delight as soon as I read the first paragraph and realized the main character, Dr. Zoe Wilder, was in Madrid, Spain. S.C. Godfrey masterfully describes some of my most beloved places in the world: Madrid and Barcelona, Spain and Paris, France. I can almost taste the jamón Ibérico from the food market stalls in Spain and the smell the Beaujolais wine from the Parisian bistro alongside Zoe and Dane. She makes me want to see Edinburgh, Arthur's Seat, and Loch na Sealga in Scotland, too.

Alongside the alluring descriptions of these legendary European cities is an interesting premise. Zoe specializes in ciphers and travels to Madrid for a cryptology conference where she soon finds herself in the middle of a life or death race to solve 5 puzzles in the famed, secretive Enigma Challenge. Aka, the Hunger Games for nerds. She pairs up with a mysterious, handsome man named Dane, and together they race across Europe, trying to solve the puzzles, escape getting killed by other Enigma Challenge players, and avoid getting their identities erased by the Challenge organizers: ProtoDark. Oh, and there's a $12 million prize for the winner, too.

The plot is fast-moving and exciting. You can clearly tell that S.C. Godfrey knows and loves these locations. She describes them accurately and adoringly. I loved the cipher-solving aspect as well because it was so different and interesting (pictures or illustrations of these in the book would be fantastic). My only pain point is that I find Zoe and Dane's relationship to be a little bit off-putting. There's not a lot of depth or chemistry there, and I don't quite believe it. To be honest, I think the relationship could develop later, over time, because I SMELL A SEQUEL/SERIES! I loved that the ending was left open and I will be first in line to read what comes next.

[Reneaue · Rating 4 out of 5]

The Enigma Challenge by S.C. Godfrey is a thrilling romp across Europe, blending cryptic puzzles with a race against time; and the ultimate threat of being “deleted.” Think Dan Brown vibes, but instead of solving a murder, our heroine is trying to prevent her own.

Dr. Zoe Wilder, an academic cryptologist specializing in literary ciphers, heads to Madrid to present her research at a cryptology conference. Fresh out of a toxic relationship with her boss, Eric, Zoe enters the annual Enigma Challenge without grasping its deadly stakes. The rules? Solve five increasingly complex puzzles before anyone else. The prize? Millions. The losers? Completely erased—degrees, accounts, social security numbers, everything wiped from existence. No wonder the competition is fierce…and dangerous.

Enter Dane Seaver, a two-time Challenge champion and millionaire heartthrob. He offers his assistance, but what’s his real agenda? Can Zoe trust him, or is he playing his own game? Together they follow the clues across Spain, France and Scotland while evading the competitors who will stop at nothing to win.

The puzzles escalate from simple substitution ciphers to more complex Vigenére ciphers with keywords, inviting readers to “play along.” The clues they reveal are cryptic yet rewarding, especially for those familiar with European landmarks, art, and cultural icons.

The story moves at a breakneck pace, mixing action-adventure with romantic tension and a dash of spice. While some twists lean predictable, the fun lies in unraveling the clues and racing alongside Zoe. It’s an engaging, puzzle-packed adventure perfect for fans of cerebral thrillers with a romantic edge.

=========================
A special thanks to NetGalley, Viking Penguin Publishing and the author for an ARC in exchange for an honest review.

[Thio Moss · Rating 5 out of 5]

Sometimes, being contrary can be dangerous. After her ex-boyfriend warns her not to enter The Enigma Challenge, Zoe Wilder doesn’t stop to consider why there is no fine print. What follows is a suspenseful race across Europe with an irresistible man and dire stakes.

Even before the challenge begins, the suspense is already simmering. We know Zoe is going to enter; we know Dane Seaver is going to be significant, but seeing things coming down the pipeline only prepares us so much. The literary cryptograms are fascinating, as is learning about various types of cryptograms. Zoe is, therefore, convincingly brilliant, albeit a bit impulsive. The controlling exes and evildoers are suitably horrific. Zoe’s relationships with her father and sister are heartbreaking, tender, and indomitable. Her new friends bring warmth and an electric anticipation. These characters sing.

The Enigma Challenge is the kind of book that’s hard to put down. It’s fast; it’s driven — excellent craftsmanship. However, there is a brief order-of-operations issue — one that the narrative acknowledges and largely smooths over, though it lingers just enough to feel like something a security expert might have caught sooner. It was momentarily jarring, but the fantastic pacing, the intriguing cryptograms, and edge-of-your-seat suspense pulled me right back in.

If you like your suspense interwoven with a little mystery, logic puzzles, and romance, The Enigma Challenge is perfect for you. It’s tremendous fun, thought-provoking, and deadly dangerous!

Thank you, Viking Penguin, for the opportunity to read The Enigma Challenge. I received a complimentary copy through NetGalley, and I voluntarily wrote this review.

[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

[Mal · Rating 3 out of 5]

Thanks to NetGalley and Viking Penguin for the advanced reader copy

3.5 stars

When Zoe Wilder shows up to a cryptology conference in Madrid, she's hoping to give a good presentation, happy that she finally ended things with her insufferable ex-boyfriend (who also happens to be her boss), and curious about whether she should enter the infamous Enigma Challenge. When she's the first person to crack the opening puzzle for the Challenge, she teams up with Dane Seavers, a two time winner and nemesis to Zoe's ex-boyfriend. Together they hop from country to country, solving puzzles and trying to stay alive. In the end, will Zoe survive and win?

This is a difficult boo to review because I was compelled to get to the end because of the intricacies of the actual puzzles that Zoe and Dane have to solve--and the third act was jam packed with action--but the rest of the book didn't hold together particularly well. Neither of the main characters was especially well drawn and the dialogue often felt too on the nose. While both Zoe and Dane comes to their partnership with caseloads of emotional baggage, they too easily trusted each other--beyond the necessity of staying alive to solve the puzzles. That said, I hope there's a second book, given the cliffhanger the first book was left on. I'd be curious to see what Godfrey thinks up, in terms of puzzle solving, in a follow-up.

The Engima Challenge is out August 11, 2026

[Meaghan · Rating 4 out of 5]

This is a review of an advanced reader copy provided by Netgalley. All opinions are my own.


Dr. Zoe Wilder, a cryptographer, is drawn into a deadly international game that tests her skills at solving puzzles. Joined by the mysterious Dane Seaver and his trio of like-minded colleagues, Zoe and Dane try to outwit other killer contestants and race against the clock in this intriguing and deadly romp across Europe.

A little bit of National Treasure and a little bit of The DaVinci Code, The Enigma Challenge tests contestants' cryptographic knowledge. If you solve all 5 puzzles, you become a millionaire; fail and your identity is erased.

The characters have well-grounded motivations. S.C. Godfrey's descriptions of the locations, monuments, and food paint vivid pictures in your mind, and it is easy to imagine our characters as they rush from venue to venue. (Don't go into this book hungry!)

The romance feels a bit rushed and shoed-in. It is almost as if the author couldn't decide if this was a romance or a thriller and ultimately threw it all at the wall to see what would stick. The last chapter felt rushed, and I couldn't decide if it ended on a cliffhanger or not - it is slightly open-ended.

All-in-all, a good fun read that will keep you guessing. A solid 4/5 stars!

[Valleri · Rating 4 out of 5]

"You have solved the kickoff puzzle." The Enigma Challenge is an infamous competition where participants solve puzzles across different countries; the stakes are impossibly high, as losing means your identity is wiped forever.

The concept was enthralling. I didn't want to put the book down! It seemed like the challenge was going to be rather simple: Navigate five puzzles in three countries over six days against numerous rivals. Um, not so much. I was exhausted by the end of the book!

Zoe Wilder, an academic studying ciphers, is unexpectedly drawn into the enigma competition. She teams up with Dane Seaver, a mysterious hacker who knows the game and its players. Win, and they receive twelve million dollars. Lose, and they face identity erasure. Puzzles, cryptograms, and ciphers are central to the plot, and the way Zoe cracked ciphers was astonishing. The pace was incredibly fast! Along the way, there were some graphic injuries, and some rather explicit descriptions of sex that made me roll my eyes.

All in all, I loved the book, and would love for there to be a second one!

Big thanks to #PamelaDormanBooks, for providing this book for consideration and review via #NetGalley. All opinions are my own. The Enigma Challenge has an expected publication date of August 11, 2026.

#Ciphers #Romance #Mystery #Thriller

[Amber Boos · Rating 4 out of 5]

So, I had to Google a lot of stuff while reading this book. If you aren't familiar with the subject matter, don't let that deter you!! If you do, you will miss out on a suspenseful, smart and fun, Indiana Jones sort of adventure! Zoe Wilder is a Dr. of Cryptology. Yes, this a thing. I Googled it. Zoe is invited to Madrid to speak at a Cipher Conference. or so she thinks. Yes, I Googled cipher too. In reality, she has been entered in a top-secret race across Europe to solve a cryptogram type puzzle. The race is called The Enigma Challenge, and the stakes are high with a $12million prize for the winner. Oh, and if you lose? Well, your entire identity will be erased. Along the way, Zoe teams up with Dane Seaver, who is no stranger to Zoe and has key information. And did I mention that he is a total jerk? This is an action-packed story! The author's descriptions of all of the countries were so cool! All places that I would love to visit. And the cryptogram parts were fascinating! I would have loved accompanying illustrations! I smell a sequel, or maybe that's just wishful thinking.

Thank you to #NetGalley, S.C. Godfrey and Viking Penguin | Pamela Dorman Books for this ARC. All opinions are my own.

[Brett Stevens · Rating 4 out of 5]

The Enigma Challenge was a fun, fast-paced read that felt like stepping into a treasure hunt movie, full of intrigue, hidden clues, and clever twists. From the start, the story pulls you into a world of cipher puzzles and layered mysteries, making you feel like you’re solving the riddles right alongside the characters. The puzzle elements were especially enjoyable and added an interactive quality that kept me turning pages to see what would be uncovered next.

While the adventure and mystery aspects were strong, the love story didn’t quite work for me and felt unnecessary to the overall plot. It didn’t detract enough to ruin the experience, but I could have done without it and would have preferred more focus on the puzzles and the central mystery.

That said, the ending absolutely delivered. It was surprising, well-executed, and genuinely caught me off guard, in the best way. I didn’t see it coming at all, and it tied everything together in a satisfying way that made the journey worth it.

Overall, The Enigma Challenge is a solid choice for readers who enjoy puzzle-driven mysteries, codes, and a cinematic treasure-hunt vibe. If you like stories that keep your brain engaged and reward you with a strong twist at the end, this one is definitely worth checking out.

[Kristin Johnson · Rating 3 out of 5]

3.5 stars

Thank you to NetGalley and Viking Penguin for providing this ARC for review consideration.

The Enigma Challenge is a fast-paced, action-movie style book. Somewhat similar to a National Treasure or Da Vinci Code, except the puzzles are part of a competition, instead of just something for historical treasure hunters. It offers high entertainment value, which is what I based my star rating on, not necessarily substance. It was fun. Nothing too mind blowing. I found all the different codes and ciphers interesting and actually feel equipped to handle my next escape room better, ha. Though I did expect them to be more complex.

I found the romance to elicit a few eye rolls. It was very cliche and predictable in my opinion. The constant predicament of getting stuck in the same hotel room was a little ridiculous, for example, as well as other things I’ll leave out for the sake of spoilers in the case that you can’t see them coming from a million miles away. The “found family” aspect also happened way too quickly and without much development.
Some of the details surrounding The Enigma Challenge seemed a little silly - such as being able to enter without understanding what was at stake.

Over all, would recommend for someone looking for a quick, light, entertaining read.

[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.🌟

[Aaron Todd Reads · Rating 5 out of 5]

I had so much fun reading The Enigma Challenge. It has everything I love: fast-paced action, clever puzzles, a sweet slow-burn romance, and an unexpected little found family that stole my heart. It reminded me of National Treasure but better characters. Zoe and Dane make such a great pair, and their chaotic jaunt across Europe had me on the edge of my seat. And bringing Xhan, Luca, and Araceli into the mix made it all even better! Each of them adds something special, and by the end I was way more attached to them than I expected. I loved that none of the characters tried too hard, and they were all easy to root for.

Also… the fight scenes? The gore?? Absolutely wild. There were moments I had to stop and go, “wait did that just happen? Ew.” but in the best way. It kept the tension high and made the whole competition feel life or death. There were some minor plot holes/ unbelievable elements but I didn’t care because I was having fun reading the story.

This book was such a blast! Fun, smart, bloody, romantic, and unexpectedly heartfelt. I’m already itching for whatever S.C. Godfrey writes next! Thank you NetGalley and Viking Penguin for the ARC 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!

[Sarah · Rating 4 out of 5]

The Enigma Challenge is a fun, fast paced thriller that hooked me right away. Zoe Wilder starts out as a quiet academic who just wants to talk about ciphers at a conference in Madrid, and suddenly she’s thrown into a secret, high stakes puzzle competition that feels like a mix of escape room chaos and international chase. Following her through each puzzle was genuinely enjoyable, and I loved picking up bits of cryptography along the way. The book also gives you a great sense of movement, and it was fun to travel internationally with Zoe as the challenge pushed her from country to country.

There’s plenty of action here—some gore, some romance, and a whole lot of mystery as Zoe teams up with Dane, the hacker who knows more than he lets on. Their dynamic adds tension without taking over the story, and the constant pressure of the competition keeps things moving. Overall, it’s an entertaining mix of puzzles, danger, and globe trotting adventure. I had a great time reading it and really enjoyed learning alongside Zoe as she fought to stay ahead in the Enigma Challenge.

[Matt W. · Rating 4 out of 5]

This one surprised me. I wasn’t sure I’d stick with it at first, but once it gets moving, it turns into a full throttle, action movie style thriller with puzzles, chases, and high stakes that are very much not theoretical.

Dr. Zoe Wilder, a cryptologist in Madrid for a conference, enters the Enigma Challenge expecting a competitive event and quickly learns the price of losing is terrifying: your entire identity gets deleted. Dane Seaver, a cybersecurity expert with history tied to Zoe’s ex, ends up as her uneasy partner, and I liked the slow shift from distrust to teamwork.

My main knock is that the early clue solving can feel repetitive, and a few characters felt a bit thin once the cast grows. The romance worked for me most of the time, but occasionally distracted from the puzzle tension I wanted more of.

That said, the second half really clicks, the pacing tightens, and the final stretch is wildly entertaining. The ending left me satisfied and also wanting a sequel.

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

[Elizabeth · Rating 4 out of 5]

Thank you to Net Galley and Viking Penguin for the ARC! All thoughts and opinions are my own!

Genre: Thriller, Mystery
Rating: 4.5/5 (rounded to 4)

I really liked this. It was so fast-paced and every chapter had you on your toes never knowing what was coming next. There were so many twists and turns that I never saw coming. The ending had my jaw on the floor in a semi cliffhanger and opens for a sequel while also being a closing for this book which is so hard to do but S.C Godfrey did it!

Dr. Zoe Wilder is an American Cryptologist who flies to Madrid with her boyfriend and professor Eric Howland for a conference. At this Conference she meets Dean Seaver a cybersecurity expert who HATES Eric. Zoe unknowingly enters a high stakes game with fatal consequence, and she has to put trust in people she just met.

This is perfect for adults who LOVED 39 clues as a child. This had the same vibes as that!!

[Sophie Mumford · Rating 3 out of 5]

This book was reviewed as a free advance copy provided by NetGalley and Viking Penguin. The Enigma Challenge has an interesting premise that initially pulled me in, but overall it didn’t quite deliver. The expected puzzle nature of the book is there at a high level, but the story often feels like you’re just watching the main character solve them rather than being drawn into the process yourself. The romance between Dane and Zoe is predictable, which isn’t a bad thing in itself, but it ends up being more distracting than entertaining. I also never fully connected with the main characters. This was especially true for Dane, who feels underdeveloped emotionally. There are also a lot of extra characters, which makes it confusing to keep track of who everyone is and why they matter. Even the twist at the end about the true nature of the challenge is fairly predictable and doesn’t really land. I liked the premise of the book but ultimately it just didn’t fully come together for me.

[Claire · Rating 3 out of 5]

A huge thank you to Viking Penguin for the ARC of the Enigma Challenge!

3.5 stars. This title was fun, fast-paced, with a cute romance! The puzzles and cryptology reminded me a bit of a Robert Langdon mystery, but from a female perspective and more romance-heavy. The main character is an academic who loves solving puzzles, but she doesn’t realize what she’s getting into with the Enigma Challenge - or with her handsome partner. This high-stakes game has the racing all over Europe, having to rely on each other as they play to their strengths.
This would have landed better with me if the writing style had been a little more serious and less casual/jokey, but that’s probably a personal preference. It just didn’t seem to fit the intensity of the storyline to me. And it was, dare I say, too fast-paced? I felt like everything happened almost too fast to feel realistic and comprehend. But, that certainly kept me intrigued and reading quickly to keep up!
Overall, a fun, intriguing read!