This book brought a major change in formatting as the author started to alternate the narrative voices (if you're a longtime reader of the blog you know how I feel about this narrative device) between Tris and Tobias. Because I had grown accustomed to reading things from Tris's perspective it was difficult for me to get into the rhythm of Tobias. For the majority of the book, I wasn't fully convinced that Roth had a good grasp on his 'voice'. The reason for this shift in formatting became clear as the action of the story was divided between the two characters and to stay with Tris would mean missing out on half of the picture (which would have made it impossible to flesh out the ending of the series). This series reminds me of Harry Potter in that as the books continue the story becomes gradually darker and the maturity of the characters is accelerated due to some (or many) struggle(s). That should give you a hint as to how this series ended. I don't want to give it away but I will say that I charged through the ending hoping that I had somehow misread what had happened or that some kind of sci-fi scenario to occur which would then fix everything. Did it? Well, I guess you'll have to read Allegiant to find out.