Mistress Jaffrey is Rosamond Appleton, illegitimate daughter of Lady Appletons late, unlamented husband, Sir Robert. Now shes all grown up, married, and ready to solve crimes on her own. She was raised by Susanna Appleton, but she inherited some of the worst traits of both her parents. Estranged from [her husband], Rosamond is shocked to learn he may be in danger. To help keep him safe, she is willing to go undercover as an intelligence gatherer for the Crown. Why not, when both her father and her stepfather did their share of spying when they were young? But when another agent is murdered, Rosamond must add crime-solving to her other responsibilities. --author's website.