After being fired from his own rock band, guitarist slacker Dewey Finn needs to raise some money to pay for his rent and his bills. When his best friend and substitute teacher Ned Schneebly is called to a temporary work in an expensive private school, Dewey pretends to be Ned and accepts the job. He finds talented young musicians in his class, and he decides to form a rock band with the students to play in a local band contest. However, he must do this secretly so that the school's principal and the students' parents know nothing about his plan…….