Blood Alone very quickly sets the tone of the plots and subplots that fill its lovely pages. The setting is World War Two and the Austra family is attempting to save the world from extinction by taking sides in a human war. Paul Stoddard is a young architect who comes to Chaves to work for Stephen Austra and AustraGlass and quickly falls in love with Elizabeth, one of the family. We are introduced to several characters that will become dear to us through the course of the book: Laurence Austra, Gregory Hunter, Charles Austra, to name a few.
I would recommend reading this before Shattered Glass, its predecessor, as it clears up a few mysteries and makes the series easier for the new reader.