Princess Ozma and Glinda are preparing to leave Oz for the Forest of Burzee, to attend the Grand Council of the fairy queen Lurline, held once every 200 years. Dorothy is surprised when Ozma appoints her to rule Oz in her place; Ozma reminds Dorothy that she is a princess of Oz, and will have the support of the Wizard.

The scene shifts to the inside of hollow Mount Illuso, next to Mount Phantastico across the Deadly Desert from Oz. Illuso is the home of the Magical Mimics; they are evil beings like their neighbors the Phanfasms. The Mimics habitually shift among strange and ugly physical forms. The Mimics have one special trick: they can copy the shape of humans simply by stepping into their shadows.