This one was a little confusing at some points. It's set over 100 years in the future and (unsurprisingly) the world has changed. These changes are never really explained. There was a Civil War in the United States that lead to at least some of the changes. There are classes - elite is one and I think army/military is considered another.
Brady seems to have a quick personality change at some point in the book. He goes from helping her to threatening her. They were on the same side until they weren't (she's a fed and he's a rebel) and maybe that's why, but it was really confusing. There was a point that I really thought he was going to be one of the heroes I end up hating. He isn't in the long run, but he came very close.