***SPOILER ALERT!*** 
 Once again Clary is out to fight the Downworlders with her 'brother' Jace. Her mother now is in the hospital still in a 'coma', and the laws of the Clave decides to butt in their life. Now that everybody knows that Clary and Jace are Valentines -former Shadowhunter gone crazy- doesn't trust them. Just like father just like Son? Well, not exactly. Like any son who discovers that his father is an evil bastard trying to destroy everything around him, well you kind of go crazy. You think the people who are around you and who loves you are in deep danger. I guess that's why he's been acting like as asshole and pissing everybody up. 
 Simon is a new vampire, and is abducted by Clary's father Valentine. Why? well he wants to raise hell on earth releasing all of the demons you can name. How? by slaying a new born Vampire, Werewolf, Fae, and Warlock. The blood (slayed by the Sword) will be used as the weapon. Well too bad that didn't turn out too well. 
 Clary now is known to create new runes (something that no other shadowhunter can do), the end of the book demonstrates her as some kind of heroine, she destroys her fathers plans by blowing up everything. Besides breaking her skull about the whole love triangle well, who can blame them? Clary and Jace were meant to be together. Simon? Well hopefully he'll fall in love with the Werewolf girl. But then again, they are brother and sister, or are they? 
 The Clave decides to take action and take Jace under custody, just so far as we know, it's just some old rag taking vengeance over Valentines son, but Jace escapes by 'Flying' or for you Jumping. She decides to trade Jace for one of the mortal instruments, and even though Jace tells her that his father would choose to kill him before he gives her the mortal instruments (A cup & a Sword) she doesn't believe him. 
 Well after the whole rescuing Jace and blah, blah, blah; the lady that works for the Clave finally contacts Valentine who assures her that she can kill Jace and she will not get the mortal instruments. That's when she realizes that she was wrong and the teenager Jace was right. Well all hell breaks lose and all Shadowhunters goes to war against the Demons and Valentine. 
 How did that turn out? well the old rag discovers the star birthmark on Jace's shoulder and goes all nutty. Well lets just say that there are more secrets to discover. I'm going to be honest and say that I hate the fact that Clary and Jace are brother, or are they? :)