For nearly 300 years, the mysterious journal of Jacobite exile Mary Dundas has lain unread—its secrets safe from prying eyes. Now, amateur codebreaker Sara Thomas has been hired by a once-famous historian to crack the journal’s cipher.
But when she arrives in Paris, Sara finds herself besieged by complications from all sides: the journal’s reclusive owner, her charming Parisian neighbor, and Mary, whose journal doesn’t hold the secrets Sara expects. As Mary’s tale grows more and more dire, Sara, too, must carefully choose whom to trust…and whom to fear.