It picks up right where, Divergent left off, which is excellent since gaps can be a bit annoying. There is tons of character development and story building. More action. Yes, more action! There is a lot that happens in this book and I don't want to give anything away! There is a huge, huge, climatic revelation. Your jaw will drop and you will be left in anticipation of what is to happen next. There are tons of twists and turns!
Tris and Four have quite a bit to deal with in this book. Things are messy, chaotic and each character has to fight there inner demons and guilt in order to move on. There are secrets that lay beneath the surface, that when emerge can destroy relationships.
This is an amazing sequel. I only wish, I didn't have to wait another year to see what transpires.