When his band votes him out due to his embarrassing musical antics, Dewey has to make the rent somehow. After intercepting a call for his substitute-teacher roomie Ned, Dewey finds himself in front of a class of elite elementary school students. Dewey decides to take on the music program and makes it his goal to teach them the gospel of rock and roll. His ulterior motive is to get them to compete against his former band for a cash prize.

A no-nonsense school administrator, Cal Peterson, threatens to shut down the music program. Lily Waite, the school's music teacher, tries to save the program by having her students put on an impressive Christmas pageant, in hopes that he'll change his mind. Meanwhile, Cal finds himself falling in love with Lily.