First, skip all that crap about Cate and her estranged sister and new boyfriend. Really, that... sub-story was just dragging and to make the book longer.
Now, focusing on Humber Boy B, this really is an interesting story. It shows how fucked up the justice system sometimes is.
I have never read anything about the life of rehabilitating teenagers after they are released, and although this book is not exactly about that, it gave me a glimpse.
I would say Humber Boy B is very realistic and well written. I am not satisfied with the end, though. Although I don't root for happy endings, I do like my books to have some closure and justice delivered. I like stories that offer some hope.
I supposed that in some obscure town of the US (or London) things would go the way it went for Humber Boy B. Sometimes I was furious (why won't you just say what happened on the bridge?).
I was so identified with Humber Boy B that I am truly sad about his end.
Just 4-stars because the story with Cat, her father and sister was not necessary. Really, you can just skip that crap.