By Kate Quinn – Spies afoot in World War II, and not all of them are who you think! Most of the story of The Rose Code takes place in December 1939, when three young women converge on Bletchley Park. They’ve been recruited for ill-defined jobs and arrive in a mixture of youthful high spirits, enthusiasm, and uncertainty. Interspersed are chapters from, November 1947, which are a day-by-day countdown to the royal wedding of Prince Philip of Greece and Princess Elizabeth Alexandra Mary, future Queen of England.

Most people today know the story of Bletchley Park (BP): how bright young things learned to decode messages generated by the German Enigma machines. Led by a collection of genius misfits and military leaders, an enormous decryption enterprise was quietly assembled. Quinn’s detailed construction of that world is riveting, not just the technical hurdles overcome, but also the human interactions in that intense and desperate effort.

Osla Kendall’s socialite mother hopes to stash her in Canada to wait out the war, but the sidelines are never a place for Osla, and she returns to London. She’s a goddaughter of Lord Louis Mountbatten and, as it happens, the wartime girlfriend of Prince Philip. (Lest you think this is a fictional bridge too far, the character Osla is modeled on the real-life Osla Benning, “a beautiful, effervescent, Canadian-born heiress and Hut 4 translator who was Prince Philip’s long-term wartime girlfriend,” Quinn explains in an afterword.)

Mabel Churt has none of Osla’s advantages, living in Shoreditch with her mum and younger sister, but she’s bright and hard-working, and, like the many summoned to BP, she’s meant to help the male “brains of the outfit” with administrative and secretarial duties. That restriction doesn’t last.

Mab and Osla are billeted in the spare bedroom of a Bletchley village house, where they meet the shy family daughter, Beth Finch. Beth is their age, but so totally cowed by her Bible-spouting mother, they feel obligated to bring her out of her shell. To her mother’s chagrin, Beth lands a BP job, and she turns out to be the best code-breaker of them all.

The work the women do is fascinating and deadly serious, yet the (mostly) young people they work with are full of life and humor. One by one, the coding systems of the Germans fall to the BP’s round-the-clock efforts. From this vital but obscure corner of the war, you view its stuttering progress: Dunkirk, the bombing of London, the naval battle of Cape Matapan, the United States entering the war, the Germans’ snarl in the Soviet Union, preparations for D-Day—the innate excitement of the story propelling you past one wartime milestone after another. By constantly grounding her plot in real events, Quinn’s narrative feels both believable and significant.

After the war, in the days leading up to the royal wedding, Osla and Mab receive a coded message from Beth. The friends have become estranged, unaware Beth is confined in a particularly horrifying mental institution. She hints at the existence of a Bletchley traitor who sold secrets to the Soviets and recalls their past friendship (‘You owe me.’) Uneasily, Osla and Map reunite, and the hunt for the traitor is on. Without all the resources of BP, they must decipher the Rose Code.

It’s a book that grabs your attention from the beginning and never lets go. I loved it!