King George IV is petitioning Parliament for a divorce from his queen on the grounds of her adultery. But rumor has it that the king secretly married Maria Fitzherbert—long before he married the queen. Now Mrs. Fitzherbert has been robbed—and she's frantically calling on Rosalind for help.

Because what those thieves took is proof that she and King George did really marry. That single piece of paper could destroy Mrs. Fitzherbert and her family—or it could prove the king guilty of bigamy.

Rosalind races to investigate. With her is ex-Bow Street officer, Adam Harkness, with whom Rosalind shares a complex and rapidly intensifying bond. But a case of theft soon turns to murder . . .

Josiah Poole, a disreputable attorney specializing in helping debtors—and who was seen entering Mrs. Fitzherbert's house—is found brutally murdered. Mrs. Fitzherbert has debts. Could she have staged the theft, and employed Mr. Poole to sell the marriage certificate? Or is the truth even more complicated?

With suspicious coincidences mounting, and more danger encroaching, Rosalind and Adam must move quickly to unravel a history-making mystery that might just lead them straight to the palace itself . . .