Sally Lockhart's friend and partner-in-adventure, Jim Taylor, has just solved a mystery. For years, he's been searching for Adelaide, the little girl enslaved by the toothless crone, Mrs. Holland, in The Ruby in the Smoke. And now he's found her—just as she's about to become a princess.

Crown Princess of Razkavia, to be exact, and a princess in danger. Her future husband is desperate to protect his bride and employs Jim as their bodyguard. Razkavia's quaint little streets are full of danger.

This thrilling conclusion to the Sally Lockhart series follows Sally's good friend Jim Taylor. Now a dashing detective, Jim has spent years looking for Adelaide, the young girl who helped Sally and her friends so long ago. The last time Jim Taylor saw Adelaide, her life was in grave danger, and when a carriage mysteriously explodes outside her new home, it seems nothing's changed.

But Adelaide is no longer a frightened orphan from the slums of England, for she has recently married a prince of a small nation—a nation at the heart of an international power struggle. When her husband is assassinated, Adelaide finds herself crowned queen—a position that seems to require all of the survival skills she learned on the streets. With Jim's help, Adelaide rules the country until political intrigue has them both on the run for their very lives, as the fate of the nation hangs in the balance.