Insurgent - Veronica Roth

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. And in times of war, sides must be chosen, secrets will emerge, and choices will become even more irrevocable—and even more powerful. 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