So. To wake her mother from the coma she's been in for, like, a bazillion pages, Clary needs to travel to the home city of the Shadowhunters: Idris (or, if you want to be all Fantasy-Twirly-Gauzey-Mystically-Capital-Lettersy, the City of Glass). Of course, Jace being overprotective Jace doesn't want her to go with the Lightwoods, but one thing leads to another, and soon enough, she's there. As is Simon the daywalking vampire. And Luke the werewolf.
The inside flap gives away much more information than I'm going to -- I'm really glad I didn't read it ahead of time, because, wow. Hello, Spoiler City. But suffice to say, Clary and Jace's incestuous feelings persist -- though she does meet a handsome raven-haired Shadowhunter who might distract her, there are many questions answered, a third Mortal Instrument searched for, Valentine's Ultimate Eeeeevil Plan is finally revealed, much banter is bantered and there is a battle that certainly beats the pants off of the "battle" at the end of Breaking Dawn.
The writing is comparable to the writing in the previous two books: fast-paced and fun, not the kind of writing that makes me want to remember lines for their well-crafted beauteousness, but the kind of writing that tells me a way entertaining story and keeps me reading even when it almost makes me late for work. One of the major strengths, for me, is that it's funny. Yes, at some points that leads to ye olde HELLO MOVIE PRODUCERS PLEASE LOOK AT ME undercurrent, but that doesn't mean it didn't make me laugh. Out loud.
Sidenote: I GLITTER HEART MAGNUS BANE. And also Simon -- which really surprised me. Because he was so emo and annoying at the beginning of the series, but by the last page, he was totally my second-fave (after Magnus, of course). End sidenote.
The Big Battle doesn't take up a huge amount of the book, but as I said, it is much more satisfying than the one in the Meyer, and the stuff (I don't want to use a word more specific than that because I don't want to give anything away.) leading up to it was actually close to what I was hoping the last Harry Potter book would give me. (See EXTREMELY SPOILERY footnote* for an explanation on that.) While there weren't any huge twists that blew me away (and really, I saw most of them coming for miles and miles... and miles), it still made me happy. My one complaint is HUGELY SPOILERY and so I'll throw it in the footnotes** as well.
I thought it was a super ending to the trilogy -- and it is the end of the trilogy, though I noticed that the author left herself plenty of opportunity to write more books in the same world (and time frame -- she's working on a prequel series right now, but maybe after that...).
*SPOIL, SPOIL, SPOILER. The teaming up of the Shadowhunters and the Downworlders, dude. The teaming up. It was awesome. And that's what I was hoping for with HP -- I wanted more of an official alliance between the wizards and everyone else. So thanks, Cassandra Clare, for retroactively giving me that. END SPOIL, SPOIL, SPOILER.
**HELLO, ANOTHER SPOILER. The character who got killed off. I thought this was kind of cheap. Because on one hand, it's the character who'd cause the most poignancy in the storyline, but on the other, it's the character that I felt I knew the least, and, even if it makes me a bad person, cared the least about. So I, as a reader, didn't really lose anything, but it was fair for the other characters to be all sad and mopey. END OF SPOILER.