AHHHHHHHH. Richelle Mead can do no wrong in her Vampire Academy/Succubus universe novels, and this is another series that's promising to be no different. 
 This is not a standalone novel, you will be really confused if you haven't read the previous novels in the series, preferably the VA novels before that, too. 
 In this book, Sydney is doing her own thing, investigating the connection between the Warriors and the Alchemists, trying to smooth of Moroi/Alchemist relations while keeping her like of the Moroi under wraps, battling her feelings for Adrian Ivashkov while fighting off attraction for Marcus, a rogue Alchemist, and fighting off the attractions of Ian, another Alchemist, while leaning magic in her spare time and trying to solve the mystery of a soul-sucking witch. Whew. 
 Even though there is a lot going on, everything in the book makes sense. Nothing is rushed, nothing is confusing; Richelle Mead is amazing at writing complex plots that don't lose the reader in translation. I've got the attention span of a goldfish, and I hate adventures that do not connect. Just yesterday, I finished a book (Green Rider by Kristen Britain) that did not do the complex-plot-lots-of-side-adventures well, and it makes me appreciate a good, clear, concise yet complex story even more. I looooooove the ending, but man, the next book is going to be a mess. Poor, poor Sydney.