This is the third book in the Tony series, which follows the Blood series. To fully understand what's going on, you should start at the beginning, but this book would probably mostly make sense if you didn't.
This has a solid plot, lots of action, and some good character development. Tony gains some adult insights into dealing with danger and into his personal relationships. The supernatural menace is believable (given that it's a world with vampires and wizards and such) and pretty cool; only I kind of cringed at the name of the dangerous situation (not the situation itself, just the name) because it seems so cliche.
I think this book is as at least as good as the previous Tony books; unfortunately, I didn't enjoy it as much. It was stretched out over too many nights of snatching 10 minutes to read a few pages before going to bed too late and getting up too early. But I base my rating on the experience I had reading the book, so I have to give it an 8 out of 10.