Lupita is excited about dancing la raspa, a Mexican folk dance, with her first-grade class at a celebration of Children's Day. But she's devastated when she learns right before the show that her partner Ernesto sprained his right ankle.

She had been practicing for weeks. And now her family won't get to see her, swishing and swaying in her beautiful dress full of colorful ribbons. Lupita sadly watches the other dancers from backstage behind the blue velvet curtain. But suddenly, she finds herself on stage, in the spot where she and Ernesto should have been. She begins to dance the routine she knows so well, holding her arms out to an imaginary partner, and almost flees when the audience laughs at her.

But the sight of her mother encourages her to be brave. She continues the dance, becoming the star of the show--at least in the eyes of her proud teacher and parents.