After Jeanie is dead, Four and Tris plans to leave the wall after see the faction try to execute the Jeanie’s men. Four and Tris manage to keep Celeb, her brother away from execution.
Also the break up of the fraction Everlyn, Four’s mother try to control her people with her method to please the mob. Peter, Tori and Christina also agreed with them to leave the wall, they success to cross the wall. But Tori is killed by Everlyn’s men.
Four and them found the red desert land behind the wall, but they also discover another city in desert. It has advance city and advance technology, they also discover that their city is just the test experiment.
They also found out about the truth of the earth, Tris found out about what her mother. Four and Christina join the force to protect the people as they told them that they are patrol in desert land to keep people safe.
Peter and Celeb are assigned to spy at the city, While Tris is assigned to work with director, David. He told her that there is a way to end the problem, Tris start to believe in him and that make Four worried.
Later that Tris learn from Celeb about war of fraction, she try to ask help from David. But he told her that he has no power to do that, they need to get help from council.
After he joins the force out he found out that actually David’s force do is kidnap children from people in desert land, then he brainwash them and make them work for him.
Four try to warn Tris about what happen, but Tris thinks that what she can do with David can help all of them. She lefts Four and go to see council with David.
Four try to go back to Chicago, but David try to kill him on the way. But Four manages to get back to Chicago.
After Tris goes with David to see council at Providence, she found that David try to used her to get more fund from them. He accepts and try to make her work for him.
David uses Peter’s ambition to help him destroy Chicago. Peter goes back to see Everlyn tells her about secret weapon, it will help her win the war. It’s a gas to make people forget everything.
After Tris found out what happen to Four and David’s plan, she decides to help her city instead by escape back to Chicago with Celeb and Christina.
They try to stop Everlyn from release the gas, but it’s too late the gas is started to release. Peter found out that David just use him, he is locked in the city with gas too.
Tris try to find the way to stop the gas while David who can control entire city and try to stop her. But finally she found the way and stop the release.
All the fractions start to unite back, they inform the other city the truth about the wall.