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. Once decisions are made, the new members are forced to undergo extreme initiation tests with devastating consequences. As their experience transforms them, Tris must determine who her friends are - and if the man who both threatens and protects her 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.