Free Audio Book : The Rose Code, by Kate Quinn

In the year 1940, as England prepares to battle the Nazis, three women from diverse backgrounds respond to the call of the enigmatic country estate, Bletchley Park. It is there that the brightest minds in Britain gather to train in the art of breaking German military codes. Osla, a vivacious debutante with beauty, wealth, and a romantic connection to Prince Philip of Greece, yearns to prove herself beyond the confines of high society. Fluent in German, she becomes a translator of decoded enemy secrets. Mab, an imperious and self-made woman from the poverty-stricken East End of London, operates the legendary codebreaking machines while concealing her own past scars and searching for a socially advantageous husband. Both Osla and Mab recognize the untapped potential in Beth, a shy village spinster who possesses a brilliant talent for puzzles. Soon, Beth finds herself soaring as one of the few female cryptanalysts at Bletchley Park. However, the ravages of war, personal loss, and the weight of secrecy threaten to tear the three women apart.

Fast forward to the year 1947, when the royal wedding of Princess Elizabeth and Prince Philip sparks a post-war frenzy in Britain. Three friends-turned-enemies are brought together once again by a mysterious encrypted letter, the key to which is buried within a long-buried betrayal that shattered their friendship and left one of them institutionalized. A clandestine traitor from their shared past at Bletchley Park resurfaces, compelling Osla, Mab, and Beth to resurrect their former alliance and decipher one final code together. However, with each petal they remove from the "rose code," they draw nearer to danger and their true adversary...