Due to the war, the factions have dissolved, and Tris and Four have discovered that their entire lives have been a lie: there is a world outside their city, beyond the fence. Tris and Four are determined to explore this new world together. However, their plan faces fierce opposition. Their love is also put to the test as they realize that the lie that defines their existence is greater than they ever imagined. In grave danger, Tris must make the final decision - and risk everything.