In the film Divergent the series: Loyal, Tris, Four and the rest of the group escape of Chicago, city that in the film is surrounded by a wall and that gives them a relative security. They have had new news that makes them leave the only city they know, leaving their families there.
Outside, you will find that Chicago lives better than outside, because outside the wall they encounter a reality that strikes them with great force. Among these realities, they realize that humanity is about to face a war of catastrophic consequences.
That makes Tris have to make very difficult decisions, because the situation does not know who can be trusted. She realizes that making those decisions changes her, but she can not do anything else.
If that were not enough, they discover that there is the Office of Genetic Well-Being, a supposed agency that isolates populations to try to find a cure, or at least that’s what they say.