The Secret Order of the Gumm Street Girls Elise Primavera
Ivy has just moved to town, hoping that after she broke that mirror 7 years ago, her run of bad luck is finally over. On Gumm street, she meets three girls whom all hate each other, and the delightful piano teacher Mr. Staccato. When he disappears in the middle of a hurricane, he leaves Ivy a treasure--the silver slippers. The real ones. The ones that fell off Dorothy's feet when she left Oz. Then Cha Cha Staccato shows up, bearing an uncanny resemblance to a wicked witch, demanding her shoes back.
The girls have to band together as they find themselves exiled to Spoz, the land under Oz.
Zany and weird, this is full of references to Oz and I would have really liked this in late elementary school. For some reason though, it just didn't click with me as an adult.