After twelve years in India, Robert, Duke of Dovedale, returns to his estate in England to avenge the murder of his mentor during the 1803 Battle of Assaye. Robert plans to infiltrate the infamous, secretive Hellfire Club to uncover the murderer's identity--but he has no idea that an even more difficult challenge awaits him, one Lady Charlotte Lansdowne.

When schoolmarm Arabella Dempsey and Reginald "Turnip" Fitzhugh, often mistaken for the elusive spy The Pink Carnation, stumble upon a Christmas pudding with a cryptic message, the pair embark on a Yuletide adventure that takes them from modest drawing rooms to a duchess's lavish 12-day Christmas celebration.