You might not want to read this review if you enjoyed this book. Just a fair warning for those who might prefer to hit the Back button. 
 Two stars only because I managed to read this trainwreck of a book to the end and the major plot twist at the end of the book made me want to find out what happens next. 
 I suppose the idea behind it wasn't half-bad but the writing was so bad even I could tell, and had problems reading it, and mind that I enjoyed Twilight. Only extremely heavy editing could have redeemed this book. I hope the next one is properly edited or I'll just read the spoilers and give up. 
 Where to start? The characters. They are all the bloody same - snarky irrational idiots. The main character Clary is Bella Swan kind of stupid. She takes everything at face value but out of the blue she has great insights to further the story. Jace is okay-ish, but often doesn't make sense either. Valentine is a very badly-written bad guy. The only bad thing we see about him is a normally oblivious teenage girl sensing that he is manipulating people. Ugh. Hodge was even stranger. I had no opinion of him troughout the book so his betrayal wasn't even a tiny bit emotional. I really couldn't connect to any of the characters. 
 The story just doesn't flow. It's a pile of dialouge interrupted by boring descriptive paragraphs. We learn almost nothing about feelings or character's motivation, we have to be told everything, nothing is shown. Hints to further the plot are painfully obvious and revelations too expected. Or just out of the blue. 
 The magic system seems to contain just about every creature and weapon imaginable but it is never ever defined. I could never tell what they are able to do and what not. What is a stele? The Covenant? Are we supposed to believe what Clary believes or question everything? It's too confusing. This book really doesn't make sense. 
 The language is also quite painful. Some words are just too out of place. Jace uses obscure language but it's never even hinted at why and it sounds really unnatural and out-of-character for the teenage boy. 
 Rant over.