The films opens with a rock band known as No Vacancy performing at a nightclub. Dewey Finn creates on-stage antics, including a stage dive that prematurely ends the performance. The next morning, Dewey wakes in the apartment he lives in with Ned Schneebly and Patty Di Marco. Ned and Patty pressure Dewey to make up for the share of the rent, which is four months overdue. When Dewey meets No Vacancy at a rehearsing facility, he finds out that he has been fired and replaced by another musician named Spider. Later, Dewey answers a phone call from Principal Rosalie Mullins, the principal of the Horace Green prep school, inquiring for Ned about a short-term position as a substitute teacher. Desperate for money, Dewey impersonates Ned and is hired. On his first day at the school, Dewey adopts the name "Mr. S" and spends his first day behaving erratically, much to the class' confusion.