Romance crackles in magical Regency London in this dazzling tale of a stolen jewel and the heroine who will do anything to retrieve it--even don a disguise and work with a high-handed-but-attractive stranger who is not what he seems. From New York Times bestseller Garth Nix! On her eighteenth birthday, Lady Truthful Newington--nicknamed "Newt"-- is dreaming about her upcoming trip to London, where the streets are filled with magic and eligible young lords. Before she goes, she is to inherit her family's treasure: the Newington Emerald. A dazzling heart-shaped gem, the Emerald contains mysterious and powerful magic. When the Emerald is stolen, Newt sets off to recover it. Her plan entails dressing up as a man, mustache included, as no well-bred young lady should be seen out and about on her own. While disguised, Newt encounters the handsome but insufferable Major Harnett, who joins the hunt for the missing Emerald. Offended by her new ally's high-handedness but eager for assistance, Newt strives to conceal her true identity from Harnett, little guessing that he too is not as he appears.

A sweeping adventure ensues filled with sinister fey, fancy dresses, witty banter, daring seaborne escapes, grand balls, and a sorceress whose evil plot threatens everyone from Newt herself to the Prince Regent. And as Newt and Harnett face danger together, each realizes there is more to the other than meets the eye--and more alarming yet, they may actually be falling in love. The New York Times bestselling author of Sabriel, Garth Nix, shares his own love for the Regency romantasy genre in a charmed world where everyone has something to hide.