Three women from very different backgrounds become unlikely friends when they are thrown together by the top-secret work being done for the war effort at Bletchley Park. Osla is a lovely, and high-spirited and dating Prince Philip of Greece, but wants to prove that she is more than just a silly socialite. Mab is a smart and ambitious girl from East London, determined to capture a better life for herself and her family. Both girls take jobs at the mysterious Park, working at different stages of the code breaking process to decipher Nazi transmissions. The two women are boarded together in the village, and there they meet meek but puzzle-minded Beth. Though they are forbidden to discuss their work, the three women bond over the secrecy of their jobs and the pressure they are under.

Two years after the war has ended, however, they are no longer friends. But when they receive a coded message warning them of a Bletchley spy, the women must reunite  and use their skills to discover who it could be before it’s too late.

I absolutely could not put this book down. The tension was perfect, so that every time I thought I had something figured out, some new information appeared, bringing more questions with it. I loved the characters, especially Osla and Mab, as well as the deep relationships they formed despite coming from vastly different backgrounds. I loved how the story was very much its own, while also including brushes with well-known historical figures (hello, Prince Philip and Alan Turing!).

All of the romantic relationships were well-written and compelling, but I was particularly taken by Mab’s. I was devastated after the tragedy of Mab losing her first husband and daughter. Their relationships were so well-written and felt very personal, and I was sad to see Mab close up again. But the ending!! I didn’t think anyone could live up to the relationship she had with her first husband, but I absolutely loved the reveal that her second husband had been involved with Bletchley Park during the war as well. Mab not only found her equal, she also found someone who understood her complicated history, which was beyond satisfying.

Happy ending meter (no specific spoilers, just the vibe of the ending):

Happy and so, so satisfying!