Tris Prior's initiation day should have been marked by victorious celebrations with her chosen faction; instead it ended with unspeakable horrors. Now unrest surges in the factions around her as conflict between their ideologies grows. War seems inevitable; and in times of war sides must be chosen, secrets will emerge and choices will become ever more irrevocable. Tris has already paid a terrible price for survival and is wracked by haunting grief and guilt.