Beatrice Prior is on the brink of a decision that will change her life. In a society divided into factions all are forced to choose where they belong. And the choice Tris makes shocks everyone, including herself.

As her experience transforms her, Tris must determine who her friends are – and who is really on her side. Because Tris has a deadly secret. And as growing conflict threatens to unravel their seemingly perfect society, this secret might save those Tris loves… or it might destroy her.