I have seen improvement in each book, from the first to this fourth, in this series. Frankly, I did not like the first book. I liked the second one. I really liked the third one--except that I found some aspects of the ending to be farfetched. This fourth book was the best of the bunch. I enjoyed it tremendously.
Curran and Kate played some mating games. That was fun, because I just adore Curran to pieces. I was frustrated at some point that Kate was too reluctant to give into her feelings. But that I was just proof that was invested in their story.
One of the things I liked most about this book is that we got to see deeper into the shapeshifter world, including shapeshifter mating and politics. Also, Kate's best friend Andrea became more of a real person, as did Kate's boss Ted. Although the bad guys were extra cool and scary, it was really the characters' personalities that made this book great.