I was provided an ARC copy of this by NetGalley.

I could NOT put this book down! Knowing nothing of cryptology and ciphers and having the most rudimentary skills at solving complex puzzles, I walked away with a much higher understanding (do not get me wrong, I could not solve these ciphers still)! The Enigma Challenge has begun. Not only are the puzzles challenging and spanning multiple countries, lives are also on the line, and romantic interests are sparking. I was so gripped by the story that I stayed up past midnight reading it. This is a MUST on your TBR.

Man, what a roller coaster ride! I loved the concept of the challenge and the consequences for losing. Zoe had the enviable affinity for code breaking/cyphers and gee she was smart. Dane was was complex, dashing, sexy and a different kind of smart than Zoe. They find themselves thrown together for a life or death amazing race. Reading about some of the locales have placed them on my bucket list!

An absolutely un-put-down-able read that left room for a possible sequel, which I would love to see! Such a great read!

Zoe Wilder is attending a conference for cryptologists when her life suddenly changes. Breaking up with her boss/boyfriend before a big meeting has really set him off. Running away with his arch enemy, Dane just adds fuel to his rage.

Zoe had heard of the Enigma Challenge but wasn't totally sure what it entailed. When she sees a box where one can sign up to accept the challenge she thinks this could be a fun exercise for her and something her deceased father would have enjoyed doing with her and so she signs up.

Once the challenge has begun, filled with cryptograms and ciphers, Zoe thinks this isn't really too hard--until Dane explains the consequences of failing - being digitally erased from existence. As the puzzles get harder and competitors get more violent, Zoe and Dane not only have to solve the puzzles, but also need to stay one step ahead of those that want to see them both dead.

Excellent tension building, with secondary characters that are more than just sketches. A blossoming romance, travels through European countries, and a constantly ticking clock to solving the final puzzle. May we have a sequel please?

If you like thrillers and puzzles then this is the book for you. It kept me thinking and I loved it so much.

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 stakes: 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 Seaver: 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?