Can someone tell me the ending?

Wesley is back in the juvi facility and he's sitting on these steps outside staring at the sunset when the other guy (his enemy) starts creeping up behind him to knife him. Then Mattie shows up just in time and adopts him. Then Wesley and Mattie and the dogcatcher (and the dog that he saved) drive home, while the other kids in juvi stare longingly through the fence as they drive home.