Jennie Lee, lead singer for the all-female rock band, Mystery, attends her high school graduation. As Jennie gives her valedictory speech, Daryle, Mystery’s bass player, is handed an engagement ring by her boyfriend Frankie. However, she turns him down. Afterward, Jennie is excited about the band’s upcoming audition at Falcons beach nightclub in Florida. During rehearsal, lead guitarist Billy announces that their keyboard player quit. Mooch, the band’s drummer, reveals that her van was wrecked after getting into a fight with gang member “Bunny” Slotz. Jennie worries about their chances of landing the summer nightclub engagement, but Mooch assure her that she will borrow another van. Later, Mooch and Billy steal Bunny Slotz’s van for their road trip. Meanwhile, Jennie goes home to her brothers, “Hubba” and “Mig.” Hubba attempts to convince Jennie to stay home and prepare for her first semester of college. However, Jennie wants one summer to follow her dream as a rock and roll performer. Suddenly, Jennie hears her neighbor, Nickie, practicing piano. She asks Nickie to be Mystery’s new keyboard player, but he insists he has only ever played classical music. However, Jennie convinces him that it will be fun. Later, the band arrives in Florida late at night, but the club is closed. Locating club owner Martin Falcon’s home, the band drives to his house and finds the door unlocked. Martin’s guard dog, Hamlet, growls at them, but Billy calms him by singing. Seeing gold records and Grammy awards around the house, Jennie realizes that it is famous songwriter Martin Falcon who owns the club. Martin appears from the back deck and tells Jennie that auditions are in the morning. Seeing as they have nowhere to stay, he offers his boathouse for the night. The following day, Martin decides to hire another band for the summer, until Jennie convinces him to let Mystery play for ten minutes. While they perform, Martin notes the audience reaction and hires them. During the summer, Daryle begins flirting with rich young men, while Billy uses drugs and keeps company with Hamlet the dog. Nickie and Mooch become attracted to one another, but Mooch tries to fight her feelings for him. Meanwhile, Martin spends time with Jennie. Although he worries that he is much older than Jennie, they start dating. He mentions that his friend is looking for an American band to tour in Europe. However, Jennie does not want to give up her college scholarship. Seeing great talent in Jennie, Martin begins songwriting again. Later, Josh, one of the club’s rich guests, invites Daryle to a pool party. During the party, Nickie gives Mooch a flower and kisses her. Meanwhile, Josh tries to take advantage of Daryle, but she knocks him unconscious, then pines for her former boyfriend, Frankie. Later, Frankie arrives in town and tells Daryle that Bunny Slotz is coming after Mooch for stealing his van. The following day, Daryle announces she plans to marry Frankie in the fall. Jennie visits Martin, but finds him with another woman named Tina. Jennie runs from the house, but Martin follows and apologizes. Forgiving him, Jennie stays the night and gets to hear Martin’s new song. Returning to the boathouse, Jennie finds Mooch, Daryle and Nickie attempting to revive an unresponsive Billy. Once she revives, Jennie makes Billy promise to stop using drugs. Later, Martin says that his friend will be coming to the club, and likely offer Mystery the European tour. However, Jennie believes the band is splitting up, and suggests moving in with Martin. Not wanting Jennie to give up her dreams, Martin tells Jennie he does not love her. Heartbroken, Jennie goes to the boathouse. After seeing her cry, Mooch, Nickie, Billy and Daryle promise they will stay with the band for her. A week later, Martin’s friend arrives as Mystery performs the club owner’s new song. Afterward, Bunny Slotz appears and threatens Mooch, but Billy, Nickie and Daryle fight him off. After police arrive and arrest Bunny, Jennie tells the band that she turned down the European offer. Mooch is upset with Jennie, but Nickie confesses he overheard Martin’s friend offer Jennie a job singing in a studio, not a tour. Later, as Mooch, Nickie, Daryle and Billy pack up a rental van, Martin tells Jennie he is happy she is going to college. As they drive off, Martin’s dog, Hamlet, runs to Billy and jumps into the van.