It's late summer, war is raging, and families are torn apart by divided loyalties and deadly secrets. In this complex and dangerous time, a young French Canadian lieutenant is captured and billeted with a Long Island family, an unwilling and unwelcome guest. As he begins to pitch in with the never-ending household tasks and farm chores, Jean-Philippe de Sabran finds himself drawn to the daughter of the house. Slowly, Lydia Wilde comes to lean on Jean-Philippe, true soldier and gentleman, until their lives become inextricably intertwined. Legend has it that the forbidden love between Jean-Philippe and Lydia ended tragically, but centuries later, the clues they left behind slowly unveil the true story.

Jacobite exile Mary Dundas is filled with longing --- for freedom, for adventure, for the family she lost. When fate opens the door, Mary dares to set her foot on a path far more surprising and dangerous than she ever could have dreamed. Meanwhile, amateur codebreaker Sara Thomas faces events in her own life that require letting go of everything she thought she knew. Though divided by centuries, these two women are united in a quest to discover the limits of trust and the unlikely coincidences of fate.