(mild spoilers)

Lots of action, and it does keep you interested in the story. But the plot makes no sense at all and I honestly couldn't relate to any of the characters; at the end of the book I was more interested in what the hell is outside those walls (and, pray tell, who's keeping the trains running?) than in what happened to any of the characters.

This book is essentially Hunger Games mixed with the Hogwarts house system of Harry Potter, but executed very poorly.