Allegiant by Veronica Roth (American, 2016)

Summary:
Allegiant narrates the story of Tris, a girl who helps to set her society free from the “faction system”, after dismissing the previous leaders and system. There is no more division within the society, but as the city was shielded by a wall there is one decision to take: to adventure out of the wall or not. Evelyn, the leader of the new system, is opposed to going out, whereas a rebellious group, Allegiant, is created and Tris and her friends sneak out of the city. They soon are found by a patrol and are taken to the Bureau of Genetic Welfare and are told the truth: their city (Chicago) was an experiment to create “divergents”, people who are pure and not genetically damaged. Tris is the only “pure” result from the experiment and is offered a position in the Council. However, her friends side with a rebellious group opposite to the “pure” and “genetically damaged” division. Tris eventually joins them and plans to take down the Bureau by spreading a serum that wipes memory. While getting her hands on the serum, she is shot and dies, but the serum is spread and everyone in the building has their memories erased. The allegiant group and Evelyn join forces and restore peace in the city, free from factions and genetic divisions, and formed by all the previous citizens plus people from the fringe, the ones that lived outside the wall.

Another summary:
The book begins immediately after the events of the previous book. The video footage revealed to the factions in Chicago says that there is a civilization outside the walls. This causes the factions to disintegrate and Factionless leader Evelyn becomes the new leader of the city. As a leader, she begins doing trials and executions of people she considers traitors, including Tris’ brother Caleb. Other leaders of previous factions form a group called Allegiant, who plan to overrule Evelyn and send people outside the city. Tris rescues her brother and escapes to the limits of the city with Four and other friends. They manage to escape the city and find Tobias’ mentor, who was thought to be dead. He takes them to the Bureau of Genetic Welfare, and they meet the leader David. 
  
  The Bureau is a government agency that is supposed to be helping fix the genetic damage that arose in the USA when genetic modification was allowed. David explains that throughout the country several cities were set up to experiment and find a cure for the genetic damage. He also says that the “Divergents” are people that have cured genes. Tris’ mother was part of the Bureau and became a volunteer to stop Erudite from killing Divergents in Chicago. Tris and her friends realize their lives have been a lie. 
  The group meets a girl named Nita, who tells them that the Bureau is not good, because they segregate people according to their genetic purity, and they create serums to do population controls in the city, like the one that helped killing people in Abnegation.
  Four then learns that he is not a true divergent, that is why he is treated as second-class, unlike Tris. He joins Nita in planning a rebellion against the Bureau leaders, but Tris realizes the plan is killing the leaders by setting off a bomb, and saves David. Uriah, one of her friends, suffers brain-damage. Tris wounds and arrests Nita. 
  
  Tris becomes a council member of the Bureau, but soon discovers that the Bureau supplied Erudite with the serums that caused the killing of people in Abnegation. Meanwhile, it is revealed that the city is in the brink of war between Johanna and Evelyn, and Evelyn is planning to release the death serum. Tris also discovers that David will release serums that can erase the population’s memory to achieve his goal of getting more funds for his experiments in the city. Tris finally helps Four in making a plan to release the memory serum in the Bureau and help the others return to Chicago and help with antidotes for the serums. 
  
  Four finds his mother Evelyn and asks her to stop the war. Evelyn has a change of heart and negotiates peace with Johanna. Evelyn exiles herself from the city. Caleb, on the other hand, wants to expose the memory serum in a suicide mission, but Tris cannot let her brother do this and she takes his place. She repels the death serum but David shoots and kills her. Four (Tobias) returns to the Bureau with Christina and Peter (Peter was given the memory serum because he wanted a second chance) and they find out about Tris’ death. Four gets depressed and plans to drink the memory serum to also erase his memory until Christina stops him. 
  Years later, Chicago is reopened and in the process of being rebuilt in a society that does not distinguish between gene purity. Four (Tobias), is now an assistant council member, Johanna is the leader, and they welcome Evelyn back from her exile. Tobias and his friends finally accept Tris’ sacrifice as they scatter her ashes.

Another summary:
This book begins with a video footage being shown in Chicago, that reveals that the civilization of the walled city is not the only one that exists, but there is also a civilization outside the walls. The previous factions in Chicago disintegrate and Evelyn (mother of Tobias “Four”) becomes the leader of the city. 
 The first thing Evelyn declares is trials and executions against traitors, including Caleb (Tris’ brother). As a retaliation, other leaders of previous factions form a group called Allegiant to overrule Evelyn and her reign of terror. Tris, as part of this group, rescues her brother and leaves the city alongside other people and they find the Bureau of Genetic Welfare. David, the leader of the bureau, teaches them that they are supposed to fix the genetic damage done after genetic modification was made legal in the United States. He also explains that “divergents” are the people who have been cured and that is why they were so special and important. David also explains that in Chicago, the Faction Erudite learnt this truth and decided to kill Divergents.
 On the other hand, a girl named Nita tells them that the Bureau is not innocent and has created serums to control the populations and that they are planning to kill people in Chicago. 
 Tobias and Nita plan a rebellion against David, but Tris finds out and stops it, which makes her become a member of the Bureau. Once Tris finally learns the true nature of the Bureau, she joins forces with Tobias to help the people in Chicago. 
 They manage to stop the war between Evelyn and the Allegiant group, but while trying to expose the truth of the serums, Tris dies (David shoots her). Tobias gets depressed, but decides to honor her sacrifice. 
 Years later, Chicago has a new social order with Tobias, Johanna at their head, that does not make distinctions between their people.

World view: The world portrayed in the story is an hypothetical society which seems to be worse than the one the author lives in.
Future projections: It’s a fearful prediction of the possible outcomes of today’s actions. Thus, it warns us against the terrible disasters (e.g. overpopulation, war, climate change) which would follow if there is no change in direction.
Ideology: The majority is oppressed by a ruling elite or an individual powergroup that come to dominate society to their own interests.
Characters, plot and writing style: The story features a rebellion against the adverse circumstances (revolutionaries may exploit newer technologies for these ends).
Classification: Non-dystopia