I ended up compromising on my rating for this one. The first 3/5ths or so of the book only rated 3 stars for me and was starting to head toward 2-star territory. I had been a little disappointed in the last book in the series, "At Grave's End" and was starting to get really worried when this 4th book of the series seemed to be struggling to find it's course. And I really didn't care for the way the main two characters kept getting into arguments over lack of communication. I can't stand that in real life and I just wish Cat and Bones would learn from their prior miscommunications.
But then the novel became totally awesome! Definitely 5 stars for the final 2/5ths of the book as it became evident the author is willing to take risks with her lead character and let the series evolve in new directions. I can't say much more about that without spoilers so just take my word for it. The next book is now a must-read.