After all that happen in the last book Tris and Four decides to get a new life. They escape the city and find out about what is outside. There they meet new people and learn new things about the world they live in. They learn about how vast they are and how there is more places like the factions. They learn how they get the factions together and how they started. They learn about the serums and how the ones that were used against then during Jeanine's attacks.They have to make the final decision, to accept what they did to their family or to fight back and do something about it.
There is romance and it is in a different world, a world in the future. This series will be great for someone who enjoyed the Hunger Games. This book continued the previous in the best way it could.