Leo Borlock introduces himself, his eccentric tie collection, and his mysterious childhood benefactor who once sent him a porcupine tie.

Stargirl Caraway arrives at Mica High. She carries a ukulele, a pet rat named Cinnamon, and decorates her desk with a tiny vase of daisies. The school doesn't know what to do with her.

Stargirl sings happy birthday to a student during lunch, and the cafeteria briefly, awkwardly participates. Leo watches. The school begins to buzz.

Leo helps run 'Hot Seat,' the school's interview show. Stargirl is booked as a guest, and the show turns hostile — students grill her about why she's so strange. She responds with complete equanimity.

Hillari Kimble, the most socially powerful girl at Mica, declares Stargirl is a fake. Her opinion carries the school. But Stargirl, at a pep rally, kisses Hillari on the cheek.

Stargirl briefly becomes popular. She knows everyone's birthdays, sends cards, cheers the Electrons to wins. Then the first turn: the shunning begins when she cheers for the opposing team.

Leo visits Archie Brubaker, a retired paleontologist who runs informal seminars in his yard. Archie has known Stargirl for years. He tells Leo about her — and asks him a question he can't yet answer.

Stargirl takes Leo to a special spot in the desert — a circle of stones where she comes to listen. He experiences the desert's silence and begins to understand how she sees the world.

The Electrons win game after game. Stargirl leads the school in cheering. For a few weeks, she is the center of the community. Then they travel to the county championship.

During the county championship, an opposing player is injured. Stargirl rushes to comfort him during a time-out, hugging him in full view of the Mica crowd. The Electrons lose. The school turns.

The school shunning reaches total saturation. No one speaks to Stargirl or Leo. Leo begins to feel the cost of proximity to her. Stargirl seems unbothered.

Leo stops sitting with Stargirl at lunch. He chooses the populated tables. He tries to pretend it is not a choice. Stargirl says nothing.

Leo asks Stargirl to change. To become normal. To rename herself. She listens, considers, and says she will try.

Stargirl becomes Susan. New clothes, a conventional name, no ukulele, no Cinnamon. Leo watches, relieved and horrified simultaneously.

Susan competes in the Arizona State Oratorical Contest. Between rounds, she dances alone to an empty floor during the band break. Stargirl is back. The audience loves her. Mica does not.

Back in Mica, the shunning redoubles. Leo cannot endure it. He distances himself completely. Stargirl leaves him gifts he finds after she's gone.

One morning, Stargirl is simply not there. The Caraways have moved. The school continues unchanged. Leo is left with the aftermath.

Years later, Leo still finds small gifts from Stargirl — sunflower seeds, a porcupine tie — left in impossible places. The enchantment continues. It always will.