Fifteen bones - R J Morgan

Jake is not a bad person-he used to be the class joker, the comedian.
He used to have "potential". But now he's been expelled from
five schools and only Cattle Rise, a tough inner-city school, will
take him. Here survival means keeping his head down, and that's
not something Jake's very good at.
Then he meets Robin, a girl with problems that are bigger and more
serious than he can even imagine. Helping Robin means entering
a dangerous, violent world.
With strong language and explicit content, this is a brutally honest,
hugely authentic new voice in teen fiction.