Stargirl opens as narrator Leo Borlock begins eleventh grade at Mica Area High School (MAHS) in Arizona, a typical high school where everyone is pretty much the same—all the students wear the same style of clothing, listen to the same type of music, eat the same kind of food, and talk about the same things. Leo, an introvert and observer, is comfortable in this conformist environment. However, on the first day of school, everyone is abuzz about a new tenth grader, Stargirl Caraway, who is wearing a ruffled, old-fashioned dress long enough to cover her shoes, carrying a ukulele, and toting her pet rat, Cinnamon, to classes. And Stargirl’s behavior only gets odder from there: on the first day of school, she starts singing, dancing, and playing the ukulele in the cafeteria. On subsequent days, her outfits include a 1920s flapper dress, an Indian buckskin, and a kimono, and she begins a tradition of serenading students with the “Happy Birthday” song during lunch.

At first, the other students are suspicious of Stargirl and avoid her. She eats lunch alone but does not seem to care. Leo, however, is intrigued by Stargirl—but not bold enough to approach her directly. Instead, he follows her after school as she walks to a house where she leaves something in the mailbox. Once she is gone, Leo looks in the box and discovers she has left an unsigned card reading “CONGRATULATIONS.” Next, Stargirl walks out of town and into the desert, where Leo follows her for a while before finally getting nervous and returning home.

One night, at a poorly attended MAHS football game, Stargirl dances barefoot on the field during halftime; then, once the second half starts, she grabs the football, dances with it, and throws it over the visiting team’s bench, to the delight of the audience. At the next football game, more than a thousand people show up—but Stargirl does not. However, Stargirl is soon invited to join the school cheerleading squad, and she agrees. At the last football game of the season, Stargirl makes her cheerleading debut to a huge audience, and she never stops cheering, even during breaks. She even joins the other team’s cheerleaders and performs wild acrobatics.

Following Stargirl’s lead, other students begin to become more active, vivacious, and individualistic—they join school activities, start new clubs, wear unusual fashions. As those changes occur, Leo is merely an interested observer, never interacting with Stargirl directly. However, Stargirl does agree to be a guest on Hot Seat, the school TV show that Leo runs with his friend Kevin. They plan to film her interview on February 13th.

In the months before the interview, however, some of Stargirl’s activities garner less-than-enthusiastic responses. When Stargirl attends a funeral for someone she does not know, the family gets angry and throws her out. When basketball season begins and the cheerleaders perform at games, Stargirl cheers for the other team as well as her own, which makes fans increasingly angry. As a result, Stargirl loses her newfound popularity, and when the Hot Seat taping occurs, it turns into a disaster.

The Hot Seat show includes a “jury” of high school students who ask the interviewee—in this case, Stargirl—questions. At Stargirl’s interview, the jury quickly becomes vicious, asking her why she cheers for the other team and why she meddles in everyone’s business whether she is asked to or not. For the first time, Stargirl actually looks hurt...