1,5/2 stars 
 Mirror mirror on the wall, who's the dumbest of them all? 
 Just by reading the summary you would thing this is an amazing book, rich of action, magic, unforeseenable events, charming characters. Involving. Spectacular. 
 Well, sorry for destroying your expectations, but... the first and only word that comes to my mind is DUMB. And if you don't believe me, just read the two quotes below, and you'll change your mind. 
 ..."I'm sorry," I blurt."What are you sorry for?" he says softly. 
 I shake my head. I'm sorry for nothing. I'm sorry for everything. 
 "I'm going with you," John says again. 
 "I'm going too," Fifer says. 
 "No, you're not," John and I say at once. 
 "I am!" 
 Is this supposed to be a kind of parody of a fantasy novel ? Because even in that case I really can't understand Elizabeth's density . Who in the world, when hunting five necromancers, starts listing all their sins BEFORE having actually captured them? And who in the world, knowing that in the kitchen there's an invisible ghost, goes right there when trying to escape? 
 Man, everything was so terribly annoying! 
 And of course we musn't forget the "amazing", "intense" and "unpredictable" romance. During the first chapters it seemed that if her crush hadn't corresponded her feelings she would have attempted a suicide, while for the rest of the book her interests have shifted "mysteriously" towards another person. How couldn't I be moved? But don't worry: there is a costant element: her unbearable victimization. 
 If all these reasons aren't enough, let's shift our attention to the plot. The adjective I would use is: plain. Almost no catches, undetailed settings, no descriptions of the wizards' powers/gerarchy/society (alas, almost all the characters) and just a little, little bit of suspance. I read until the end just to verify if the ending could become even worse than the beginning (which didn't, fortunately), and I put two stars because... well, usually one star is reserved only to DNF readings.