Tris's initiation day should have been marked by celebration and victory with her chosen faction; instead, the day ended with unspeakable horrors. War now looms as conflict between the factions and their ideologies grows. Transformed by her own decisions but also by haunting grief and guilt, radical new discoveries, and shifting relationships, Tris must fully embrace her Divergence, even if she does not know what she may lose by doing so.

Tris and Four are now fugitives on the run, hunted by Jeanine, the leader of the power-hungry Erudite elite. Racing against time, they must find out what Tris's family sacrificed their lives to protect, and why the Erudite leaders will do anything to stop them. Haunted by her past choices but desperate to protect the ones she loves, Tris, with Four at her side, faces one impossible challenge after another as they unlock the truth about the past and...