London's social season is in full swing, and Victorian aristocracy is atwitter over a certain gentleman who claims to be the direct descendant of Louis XVI and Marie Antoinette. Adding to their fascination with all things French, an audacious cat burglar is systematically stealing valuable items that once belonged to the ill–fated queen.

But things take a dark turn. The owner of one of the pilfered treasures is found murdered after the theft is reported in the newspapers, and the mysterious thief develops a twisted obsession with Lady Emily Ashton. It takes all of Lady Emily's wit and perseverance to unmask her stalker and ferret out the murderer, while faced with a brewing scandal that threatens both her reputation and her romance with the dashing Colin Hargreaves.