Walker isn't a cop anymore and after the first one we sort of know why don't we?
But then he becomes a contract worker of the DEA or immigration and enlists an old friend to have his record cleared and that is about it. Nothing really comes from it.
He has a crush on a woman who is working both sides of things and saves her by... driving a car into a boat.
Yeah, it makes about that much sense, but, hey, Deadly Little Miho is in it and she really needed to stick around, she would have been a bright spot on this franchise.