Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Engrossing...yet ultimately unfulfilling

I read this book quickly, as I usually do with the Anita Blake series - it drew me in, and I finished it in two days. Once I was done, I found myself thinking about the plot, and realized that there isn't one. Anita does not raise any zombies, execute any vampires, solve any mysteries for the police. The entire book is Anita having sex in different ways, with different men, and either gaining new powers or a deeper understanding of the ones she already has. While the "is she or isn't she pregnant?" drama was an excellent way to further the relationships she's already in, watching the various men in Anita's life react to her possible pregnancy and her sexcapades does not equal a storyline.The earliest Anita Blake novels had plenty of plot but no emotional depth or interaction; the most recent ones are nothing but finding new men for Anita to sleep with and new ways for her to do it. Did this series peak somewhere around "Obsidian Butterfly"??