Tally’s central dilemma is over loyalty and betrayal: Will she betray her friend, Shay, or stay ugly forever? Like any teenager, Tally desperately wants to fit in. She sincerely feels, as her society has instructed her, that once her physical flaws are corrected and she is made certifiably “beautiful,” she will finally have inner peace and a life full of fun and free of responsibilities. When Dr. Cable gives Tally the ultimatum to betray Shay and the Smoke or stay ugly, the decision becomes relatively easy for Tally. She feels that turning them in is doing “right” by Shay by saving her from a lifetime of being ugly, and by saving other Uglies from their misguided attempts to be free. Tally believes that her society’s ways are the best. But when she arrives at the Smoke, she discovers that life is more complicated than she imagined. 

Once Tally learns about the brain lesions purposely implanted by her society into people’s brains, and learns that beauty is more than skin-deep with her romance with David, she discovers the value of independent thinking that goes beyond what her society instructs. Tally learns that self-preservation is not about keeping one’s interests intact, but about keeping one’s mind, integrity, and loyalty intact. Tally undergoes an intense emotional transformation throughout the novel. She develops endurance and courage, and takes risks that go beyond simple adolescent “tricks.” She makes the ultimate sacrifice by turning herself in so she can be a willing subject in Maddy’s trials, and in doing so, make things right with her friend Shay.