What a dismal book. It was very much like the Divergent trilogy, but with The Immortal Rules elements thrown in (small band of kids searching for a "promised land," while trying to avoid being hunted down, a heroine who thinks she's a danger to her traveling companions and that they'd reject her if they knew what she really was, etc.) 
 It wasn't a totally dark and hopeless book, though. Enough positive things happened to keep the book from being stuck in a circle of hopelessness and dashed plans. There was plenty of action, suspense, and heartbreak. The characters were all well-defined and likable. (And when I say "all," I mean "exclusively Ruby's group." Everyone else was a total creep.) 
 I'll definitely seek out the next book in the series, but I think I need to read something a little more lighthearted in the meantime. No matter how well-written, dystopian novels always leave me feeling a little bleak.