A royal palace. A closed book. A betrayal that will echo through generations…

Windsor, 1940: 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: Looking through her grandmother's papers, Lacey Jones comes across a mysterious letter stamped with the Windsor Castle crest. But how did it come to be in her family's possession?

And so begins a journey that will take Lacey deep into the heart of the oldest inhabited castle in the world, and change her life forever…