I have a odd relationship with this series. I purchased them all on sale and sat down to buddy read them with a friend, but over the course of the series it started to go downhill. The buddy read wound up drifting away, but we still talked about the series. If they hadn't said something along the lines of "I don't think this series is for you and you shouldn't finish it", I probably would have abandoned it long ago. Instead, those words acted like a red flag in front of a bull, making it a vendetta to finish the series now!
Sadly, while this installment is somewhat emotional, it is also rather boring. Big bad guy after Cat, she spends most of the book acting clueless and whiny, spinning her wheels to solve the problem when she's got most of the puzzle given to her, then she gets a flash of insight at the end of the book and PRESTO! problem solved. What saved this from a one star rating was the string of zany one liners and a reference to the movie A Cinderella Story: Once Upon a Song. I especially liked the role Marie Laveau took in this story. I think she is a formidable force to reckon with and look forward to seeing where she takes things now. That alone will keep me reading the series to the end!