Wow, what a story.  If you're looking for a fun mystery, this is not your book.  This is the story of an extremely dysfunctional family living in a sprawling manor house in Cornwall.  The father, Adam Penhallow, is a manipulative tyrant who delights in baiting each one of his children until they explode.  I agree with one other reviewer that the expository portion of the book is hugely long, during which Heyer creates each character down to a refined brush stroke, and illustrates how poorly equipped they are to deal with one another.  This includes Faith, the old man's second wife.  Faith is at first a sympathetic character but she soon becomes pathetic --- like many of her Penhallow relations.  I am frankly not sure I could recommend this book as heartily as I have done with almost all of Heyer's books.  There is something so grindingly tragic about this story.  In many ways it reminded me of An American Tragedy by Theodore Dreiser .... a dark book indeed.