Tally lives in a world where your 16th birthday brings aesthetic perfection: an operation that erases all your flaws, transforming you from an "Ugly" into a "Pretty". She is on the eve of this important event and cannot wait for her life to change. As well as guaranteeing supermodel looks, life as a Pretty seems to revolve around having a good time. But then she meets Shay, who is also 15 - but with a very different outlook on life. Shay isn't sure she wants to be Pretty and plans to escape to a community in the forest - the Rusty Ruins - where Uglies go to escape "turning". Tally won't be persuaded to join her, as this would involve sacrificing everything she's ever wanted for a lot of uncertainty. When she is taken in for questioning on her birthday, however, Tally gets sent to the Ruins anyway - against her will. The authorities offer Tally the worst choice she could ever imagine: Find her friend, Shay, and turn her in or never turn Pretty at all. What she discovers in the Ruins reveals that there is nothing "pretty" about the transformations..