This book had some serious ups and downs. The main reason I had to take so many stars from it was that I honestly had to skip some parts. It got descriptive to the point it was tedious and I found myself jumping ahead to the "fun" parts. 
 Around the middle of the novel it got better, both in action and romance. There were many "enemies" and I changed my theories in each chapter. The plot twists kept it interesting, as opposed to previous novels when it was too predictable. 
 What I still don't get is who was the protagonist here. I thought the focus would be on Simon, whom I like, but it frustrated me how the author doesn't really expain his feelings for the two girls, only for Clary -over and over. It seems like he was being with them just because he could. Approaching the end we see him leaning towards one of them but not because he had a life changing epiphany or a sudden attraction or electric scene, just because. That love triangle makes absolutely no sense, there was no chemestry at all there, though I very much love those characters, Izzy in particular and would love to see them as an item. 
 That being said, our favorite semi-incestuous couple provided tons of hot scenes with loads of chemestry, and yet this was all shadowed by Jace's self-destroying nature. I mean, I get Clary's supposed to save him for himself, but how many more excuses can the guy make for giving up on the relationship? It's like she's the only one fighting for it. I'd much rather her have a little pride and not having to beg for him to be with her every two days. The only moments she confronted him was to accuse him of dumping her. You dump him for a change and see how he stops whining. 
 All in all, I believe there were a lot of good ideas behing this novel but I don't think they were carried out right.