In Beatrice Prior's dystopian Chicago world, society is divided into five factions. On an appointed day of every year, all sixteen-year-olds must select the faction to which they will devote the rest of their lives. Beatrice makes a choice that surprises everyone, including herself.During the initiation that follows, Beatrice struggles alongside her fellow initiates to live out the choice they have made. They must undergo extreme tests of endurance and intense psychological simulations. But Tris also has a secret that can mean death. Soon she learns that her secret might help her save those she loves . . . or destroy her.