Assassin's Masque (Palace of Spies)

Blurb

Things are turning around for seventeen-year-old Peggy Fitzroy, a once-orphaned spy. Her father is back from the dead, and her unwanted engagement has been called off for good. But when a mysterious veiled woman shows up, Peggy uncovers a fresh slew of questions about her past, present, and future.
Now Peggy is back at the palace, unsure of the loyalties she thought she held. With the Jacobite uprising stalking ever closer to the throne, it’s imperative that Peggy discover who she can really trust. Can she save herself and the royal family, or is she doomed as a pawn in this most deadly game?