Heirs and Graces by Rhys Bowen, 295 pages

I'm a big fan of the Lady Georgiana Rannoch mystery series. As 35th in line for the crown, Georgiana is unlikely to ever rule, but it does mean she can't really work for a living but is expected to live up to a certain standard. So when she is invited to a posh estate to help groom a long lost heir from Australia, Georgiana jumps at the chance, especially when Darcy turns up. But a murder quickly follows with the heir as the prime suspect. Georgiana and Darcy must work together to prove the Australian heir's innocence and find the murderer before they strike again.