Viola Hastings is a high schooler who loves playing soccer. Her boyfriend Justin even tells her, in confidence, that she's better than half of the guys on his soccer team. When the girls' team gets cut at her school and Justin refuses to advocate for her in front of his teammates, she breaks up with him and decides to take matters into her own hands. Her twin brother, Sebastian, is secretly going on tour in London with his band, and Viola decides to impersonate him, taking his place at the neighboring school, Illyria, in hopes of playing boys soccer there.
With the help of her friends Paul, Kia, and Yvonne, Viola turns herself into a boy, "Sebastian," and starts attending Illyria. She is roomed with a hunky soccer player, Duke Orsino, who wants nothing more than to woo and date the beautiful Olivia, Viola's lab partner. Duke agrees to help Viola (who he thinks is Sebastian) make the first string soccer team, in exchange for Viola putting in a good word for him with Olivia.
In the course of Viola trying to help Duke, Olivia falls in love with her. When Viola shows no interest in her, Olivia begins to flirt with Duke in hopes of making Viola jealous. One day, at a carnival, Viola, dressed as herself, takes a place at the kissing booth, where she kisses Duke, who has no idea she is also "Sebastian."
When the real Sebastian returns to Illyria a day early, Olivia kisses him, thinking he is the guy she's been falling for over the past few weeks. Duke sees the kiss and throws Viola out of the dorm room, thinking that Viola has betrayed his trust.
On the day of the big game against her old school, Viola accidentally oversleeps. The real Sebastian, who is bad at soccer, plays in her place. During halftime, Viola pulls Sebastian aside and gets him to switch places with her so she can play the game. When Duke refuses to pass the ball to Viola, still angry about Olivia, she reveals to him that she is actually a girl, and that she didn't kiss Olivia after all. They finish the game, and in a definitive moment, Viola scores a goal.
Viola has to participate in a debutante ball, and invites Duke, unsure if he will forgive her and come. He does, and they walk down the runway together, officially a couple.
