Sarah Zettel’s Palace of Spies tells the story of Peggy Fitzroy who was orphaned as a child and has lived with her Uncle and Aunt Pierpont and her beloved cousin Olivia ever since. At 16, her Uncle Pierpont announces that she is to marry Sebastian, the second son of Lord Sandford, and a much desired husband by her peers. Peggy is dismayed at the news but reluctantly agrees, despite never having met Sebastian. When they do meet at the social event of the season, he tries to assault her, and she is saved by a man named Mr. Tinderflint. Tinderflint tells her that he once knew her mother and implores her to take a post at the court that he has arranged for her. She refuses and runs back to the party. When Sebastian demands an apology the next day, she refuses and calls off the engagement, leading her uncle to kick her out of his house.
Left with no other options, Peggy remembers Mr. Tinderflint’s offer and decides to pay him a visit. When she reaches his address, she finds out that his offer is more complicated than it initially seemed. Her job is to assume the identity of the deceased Lady Francesca Wallingham, to whom she bears a striking resemblance. Francesca, one of Princess Caroline’s maids of honor, and a spy for Tinderflint and his associates Mr. Peele and Mrs. Abbott, passed away while visiting her home, leaving them without their spy at court. After enough training to portray Francesca, Peggy sets off for Hampton Court where she begins to question whether the real Lady Francesca Wallingham died of natural causes, as she was told, or if the lady was murdered. As she investigates Francesca’s demise and the loyalties of the court, readers are treated to a captivating mystery filled with intrigue, suspense and romance.