Windsor, 1940: War rages, and as bombs rain down across Britain, nowhere is safe: not even a royal palace. Secretly tasked with foiling a suspected plot, Sophie Klein is placed in the Royal Library at Windsor castle, where the princesses reside. But when she learns that Windsor is compromised, Sophie must sacrifice everything she knows to save the future queen of England. Philadelphia, Present day: Digging into her great aunt’s family tree, Lacey Turner comes across a mysterious book bearing the stamp of Windsor Castle’s royal bindery. But how did it come to be in her family’s possession?

Italy, 1940. With Florence on the cusp of war, Il Scorpione, the no-nonsense Englishwomen of the city, find their genteel livelihoods under grave threat by the approach of the Nazis. Tea rooms and bookshops are closed by the Fascists, and the women are forced to join the war effort. Desperate to help in any way that she can, Angelina Leone, expert art-historian and the half-Italian niece of Il Scoprione’s founder makes a deal with the devil.

Morocco, 1928. Marie-Madeleine Méric is not the kind of woman who stays quietly at her husband’s side. Polyglot, pianist, and pilot, she is a woman of many skills, with unconventional interests—like driving in car rallies—that earn her a daredevil reputation. But dabbling in intelligence work to assist her military officer husband and the French government helps her recognize who she is at heart: an adventurer.

Freya, Callum, Mischa, and Victoria have nothing in common—well, except for one thing: they’ve each experienced a deep personal loss that has led them to an unconventional group meeting, every Tuesday night at seven. A meeting they’ve been particularly selected for that will help them finally move on. At least, that's the claim. As they warily eye one another and their unnervingly observant group leader, one question hangs over them: why were they chosen?

Juliette and her husband have finally made it to France on the romantic getaway of her dreams—but as the days pass, all she discovers is quite how far they’ve grown apart. She’s craving a new adventure, so when she happens across a tiny, abandoned shop with a for-sale sign in the window, it feels fated. And she’s about to learn that the forgotten bookshop hides a lot more than meets the eye.