Recruited by the Jockey Club to investigate rumors of race fixing in Newmarket, Suffolk, Dillon is startled to discover that a gorgeous young Irishwoman calling herself Priscilla "Pris" Dalling (in reality an earl's daughter) is trying to get a look at the two official tomes on breeding and racing in England, the Breeding Register and the Stud Book. The green-eyed femme fatale is determined to help her twin brother, Lord Russell Dalling, whose dream to train an Irish Derby winner for Lord Cromarty's stables has landed them both in heart-stopping danger.