Unbreakable is the edge-of-your seat true story of the codebreakers, spies, and navy fighters who helped defeat the Nazis and turned the tide of World War II-perfect for fans of The Imitation Game, Alan Gratz, and Jennifer Nielsen.

"A thrilling adventure of intrigue and daring worthy of the best James Bond stories." -James Ponti, New York Times best-selling author of City Spies

As the Germans waged a brutal war across Europe, details of every Nazi plan, every attack, every troop movement were sent over radio. But to the Allied troops listening in-and they were always listening-the crucial messages sounded like gibberish. The communications were encoded with a powerful cipher, making all information utterly inaccessible . . . unless you could unlock the key to the secret code behind the German's powerful Enigma machine.

Complete with more than sixty historical photos, Unbreakable tells the true story of one of the most dangerous war-time codebreaking efforts ever. While Hitler marched his troops across newly conquered lands and deadly "wolfpacks" of German U-Boats prowled the open seas, a team of codebreakers, spies, and navy men raced against the clock to uncover the secrets that hid German messages in plain sight. Victory-or defeat-in World War II would hinge on their desperate attempts to crack the code. Perfect for fans of Bomb, The Boys Who Challenged Hitler, and The Nazi Hunters.