Woah Nelly is this an overwhelming and fun book. There's so much going on. There are plots within plots, betrayals, neat surprises and enough action to satisfy a junkie. By the end of the novel our heroine Carmella will have really come into her own, a kick-a** heroine supreme who has learned much about who she truly is (though much more clearly remains) and has gained the key to vast powers (though not really yet the control). I'm going to hold off describing more as I don't want to reveal any of the surprises (I've been trying to be very careful so far to not do so as it's really hard). Leave it enough to say that this is a wonderfully crafted story with great characters, friend and foe (though not always clear which is which), which was a total pleasure to read.
You must read the series book 1, Binding Magyk, before this one, but you don't really need to have read the predecessor Gatekeepers Chronicles series. I haven't - yet - though I suspect that would've enhanced this series if I'd read it before starting book 1. As for this book, if read in order after book 1 it will easily be a five star read and thus I'm happy to highly recommend it.