Specials (Uglies #3) by Scott Westerfeld

Tally has become a Special, hunting the Smokies who had helped her and Zane before they were discovered with the Smokies. Now everything revolves around finding the New Smoke. But Tally loves Zane and wants him to become a Special just like her, but suffers from the brain damage caused by the pills they took as Pretties. To monitor Zane, the city has outfitted him with an unbreakable necklace, so to prove how Special he really is, Shay and Tally break into an armory to steal something that will destroy the necklace, but inadvertently destroy the armory, making the city believe that they are under attack from a different city or the Smokies. Tally and Shay release Zane, who then go with a pack of Crims to the New Smoke. Both Tally and Shay track them, but soon Shay goes ahead of the Crims while Tally stays to make sure Zane is okay. Eventually, the New Smoke is reached and instead of being a small camp in the wilderness, is a whole city. Tally finds that Shay and the other Specials that are with her (known as Cutters) have taken something to cure them of their icy mindedness. Tally doesn't want to change and fights it, and leaves the city to go back to Special Circumstances and confesses who really destroyed the armory. Does Tally ever find her place in society?