OMG!!! i died and went to heaven when i saw this at my local bookstore and was able to get it early :D It was AMAZING and lived up to my expectations. 
 It starts of with jace missing, along with sebastian, and the rest of the gang working hard to locate them. The plot was good with all the characters having an integral part to the plot. It also had a lot of twists towards the end that i loved. 
 All the characters were just as awesome as ever; i loved how hard clary worked to save jace and was willing to take massive risks for him. Jace has changed a lot - he is under the influence of sebastian which means that a bit of his evilness has leaked into his personality. I kinda missed the old one who was extremely sweet but it was a refreshing change to the jace in COFA. Nevertheless, he was still funny and HOT!!! Sebastian is one of te BEST villains ever!!! He was totally evil and rocked it, but at the same time you sort of see his other side that is lonely and wants jace and clary to be on his side. 
 The others were great too with simon being one of my favs. You see a softer side of isobel, as her and simons relationship progresses. Unfortunately for malec fans, their relationship really suffers in this one that i blame alec's insecurities for. 
 It was nice having a slightly different setting in this one as jace, sebastian and clary travel around the world from venice to prague to paris. The romance was scorching HOT with the DSCS and other hot scenes eventhough clary and jace dont have the best relationship in this. you also find out that jace isnt a virgin ;) lol 
 The plot gets really good towards the end of the book with an epic showdown that leads to the events in the next book, gauranteed to be earthshattering. It ends in a cliff hanger but its not as bad as the last one. you will definitely love this book so i suggest u run to your bookstore as soon as possible :)