Stargirl is about the conflict between conformity and individuality, about what happens when an utterly unique, couldn’t-care-less-what-others-think character enters a close-minded, insular environment. Leo, the novel’s narrator, acknowledges from the beginning that his high school is not a bastion of individuality. Not only do students follow the rigidly prescribed trends in clothing, food, music, and more, but the most popular kids are idolized precisely because they are not unique—they do nothing “special.” Rather than feeling stifled in this environment, Leo appreciates it: he knows precisely how to act, and as long as he sticks to “normal” behavior, he is guaranteed acceptance in the high school community.

The arrival of Stargirl Caraway brings upheaval to Leo’s life—and to the entire school. At first, the students regard her with curiosity and distrust, some even refusing to believe her behavior to be genuine. Hillari, the most popular girl in school, insists that Stargirl is an actress planted by the school administration to stir things up and get students more involved. And, of course, no student is willing to risk his or her place in the school community by actually interacting with Stargirl—her lunch table remains empty.

However, what makes Stargirl even more unusual is that even after the other students’ disapproval becomes clear, she refuses to change her behavior. To the astonishment of everyone around her, Stargirl actually does not care about being liked or accepted by the larger group. At the same time, Stargirl does care very much for other people: she gives presents to the entire school on holidays, sings the “Happy Birthday” song to students on their birthdays, and leaves congratulatory notes and gifts for people she does not even know.

Eventually, Stargirl’s kindness and enthusiasm for life starts to penetrate the conformist community, and at first, the changes appear to be positive. When Stargirl becomes a cheerleader, she awakens school spirit at formerly poorly attended sports games, and for the first time ever, the school basketball team finds itself on a winning streak. Students join school clubs, try out for the school play, dare to express their own individuality—and they begin to accept and even befriend Stargirl.

Unfortunately, Stargirl’s popularity lasts only briefly. Students begin to resent Stargirl for the same quality that attracted them to her in the first place—her huge, open heart. Students cannot understand why Stargirl cheers for the opposing team at basketball games, why she attends funerals for people she does not know, and, especially, why she runs to comfort an injured basketball player from the opposing team. To the conformists, Stargirl’s behavior appears to be betraying the larger “group,” and they blame her when the basketball team begins losing again. Stargirl, on the other hand, sees people as individuals all worthy of love, rather than “groups” pitted against each other, and cannot understand the animosity directed toward her.

The students’ distrust of Stargirl reaches a head at the Hot Seat taping, when students have a chance to confront Stargirl directly. Their attack reveals one of the central ideas of the novel—that groups of people find nonconformists threatening because the group feels attacked, judged, and rejected; the conformists believe the individual is directly challenging their behavior and values. One student tells Stargirl, “you don’t like us, do you?” while another asks if there’s something wrong with the group, that she’s “gotta be so different.”

In the second half of the novel, Stargirl begins to pursue Leo directly, and another thematic quandary is raised: what happens when a former conformist, a member of the “group,” begins to associate with a nonconformist like Stargirl? When Leo is alone with Stargirl, he finds himself opening up, learning to enjoy life, thriving as an individual; however, he cannot let go of the fact that in front of the “group” at school, he is now shunned along with Stargirl. For a brief time, Leo even convinces Stargirl to act and dress “normally,” but the attempt is a disaster: Stargirl constantly has to ask Leo what “normal” behavior would be, she becomes unhappy, and yet still she is rejected by the school. Eventually, Stargirl gives up and goes back to her real self, telling Leo she will understand if he does not want her anymore.

At this point, Leo realizes Stargirl will never truly be accepted by the school. He knows he should stick by Stargirl, show her and the world he appreciates her and that he is not afraid to be different, but he cannot find the courage. In the end, Leo chooses the group over Stargirl, avoiding her and choosing not to ask her to the school dance. And after the dance, Stargirl disappears, never to be seen by Leo or any of his classmates again. With this turn of events, the author implies that someone as unique, as utterly and unapologetically individual as Stargirl, can never find a permanent place in a conformist society.

The novel ends with an older Leo reflecting back, wishing he had acted differently, and hoping he will get another chance with Stargirl. However, despite his regrets, Leo still acknowledges the effect Stargirl had on him. In their short time together, Stargirl taught him to see the world differently, to really experience things, to ask questions, and to embrace life. Thus, the author ends the novel with a celebration of the nonconformist’s power to open up our world—and the hope that readers will not squander their chances with potential Stargirls the way Leo did.