Empire of Bones
Not to be confused with The Empire of Bones (inheritance).

Empire of Bones (Random House) released in 2013, is the third book in the Ashtown Burials series. In this book, Cyrus Smith and his sister Antigone Smith are trying to discover what they have inherited from their godfather, William Skelton. Them and their friends are all that stand between Radu Bey opening The Burials and Dr. Phoenix taking over the world.