When all the girls and boys in the neighborhood take up musical instruments, at first they produce awful tones, but after much practice they are able to come together as a marching band that brings brassy, classy fun.

When Olivia learns that there will be no band at the evening's fireworks display, she decides to form one of her own, with herself as the only musician and some rather unusual instruments.

A silver-tongued swindler cons the people of River City, Iowa, into buying expensive musical instruments and uniforms for a planned boys' marching band. His scam is complicated by his feelings for the local librarian, who is also the only person in town who knows anything about music.