In the world of Uglies once you turn sixteen you also get to turn “pretty”. That is you undergo surgery that’ll get rid of all your old imperfections and instead make you beautiful according to the conventions of evolution and society. In book one Tally was the last of her friends to turn sixteen, and so was left alone when they all turned Pretty and moved to Pretty-town.
Spoiler warning for book one in effect.
Tally Youngblood is an Ugly. All her friends have gone off and become Pretties, but she is the youngest, and eagerly awaiting her 16th birthday so that she can join them. But before she reaches that magical age she meets a new friend, Shay, who tells her about a mysterious boy called David, and the notion that some people don’t want to be made Pretty. To Tally this is insane. Science and evolution prove that people like beauty. And back in the “Rusties” day, when they weren’t able to make people pretty there was so much discrimination just over the way people lived. She’ll never go off looking for the Smoke. She’ll stay in the city, and become Pretty, just like all her friends.
Of course, if she did then this book wouldn’t have much of a plot now would it?