Featuring multiple chapters narrated alternately by Tris and Tobias (Four). These passages detail the immediate aftermath of the previous book, focusing on the protagonists' escape from the city ruled by Evelyn and the factionless, and their journey to the Bureau of Genetic Welfare outside the city walls. The narrative explores personal relationships—especially the strained dynamic between Tris and Tobias, and their interactions with friends like Christina and Uriah—alongside major plot revelations concerning the origins of the faction system, genetic experimentation, and the true purpose of their society. Key events include Tris's discovery of her mother's past at the Bureau, Tobias's struggle with the revelation that he is "genetically damaged" (not Divergent), and their involvement with an attempted rebellion led by Nita that ultimately results in a tragic outcome for Uriah.