At the story's start. 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. The copied people are paralyzed as a result.
The Mimics are ruled by King Umb and Queen Ra (a play on "umbra," shadow). Since the Mimics are inherently evil, they are also inveterately hostile to all things good, including and especially Oz. Ra has a plan for circumventing the magic safeguards that prevent the Mimics from attacking Oz. The Mimic royals and their minions fly to the Emerald City in the shape of big black birds. Surprising Dorothy and the Wizard, Ra and Umb quickly duplicate them, and their followers carry the two paralyzed victims away to Mount Illuso. In these borrowed shapes, Umb and Ra rifle through the magical records of Oz, looking for the antidote to the magic spell that controls them.
The two royal Mimics cannot imitate the Wizard and Dorothy convincingly. People become suspicious, and Toto exposes them as impostors — but not before the Mimics find what they are looking for. Back in Mount Illuso, they conjure a giant red spider that spins a magic web; this counteracts Lurline's magic and allows the Mimics to attack Oz en masse.
Dorothy and the Wizard are imprisoned in a cave deep within Mount Illuso. Suddenly, a brilliant fairy light appears, freeing them from paralysis. The light comes from a button on the cave wall. They press the button, and a hidden door opens to an elevator, operated by a living wooden puppet, Hi-Lo. He carries them upward to the top of the mountain, where the two Ozians discover the town of Pineville, filled with other animated puppets. They meet Ozana, the fairy delegated by Lurline to watch over the Mimics. Ozana has filled her lonely days and years by creating her puppet people and her Story Blossom Garden. Ozana is shocked to discover that the Mimics have evaded her guardianship; she leads the Wizard and Dorothy back to Oz, flying on giant swans.
The Mimics arrive in Oz as beautiful birds, with gorgeous plumage of "Red, blue, green and gold...." The residents are seduced by their beauty; the Mimics quickly duplicate and paralyze them. The Cowardly Lion, the Hungry Tiger, and other animals are magically sedated; the Scarecrow, the Patchwork Girl, and other non-humans are simply tied up. The Mimics have largely completed their conquest when they simultaneously confront the arrival of Ozana, Dorothy, and the Wizard, and the return of Ozma and Glinda. Ozana's magic is powerful enough to subdue Ra and Umb and reverse their spells. The Mimics are sent back to their mountain. Order is restored to Oz.
Ozana is rewarded with an invitation to live in Oz. Her Story Blossom Garden and her wooden puppet people are magically imported to keep her company.
Snow was the fourth Royal Historian of Oz. In attempting to revive the flagging Oz franchise, he chose to ignore all the characters and situations introduced by his predecessors Ruth Plumly Thompson and John R. Neill, and return to the original inspiration of L. Frank Baum. Dorothy is returned to the role of primary protagonist, precisely because she is Baum's great heroine.
Snow relied heavily on Baum's sixth Oz book, The Emerald City of Oz, for his inspiration; he makes the relationship between the two books overt and deliberate. In the eleventh chapter of his book, Baum wrote that "Erbs are the most powerful and merciless of all evil spirits, and the Phanfasms of Phantastico belong to the race of Erbs." Snow picked up on this hint, to create another breed of "Erbs" as the villains in his plot.
Snow's first effort at Oz fiction was not a commercial success, however. Publisher Reilly & Lee had hoped to return to the pre-World-War-II schedule of annual Oz books — but a new book in 1947 would have competed with the unsold stock of Magical Mimics. As a result, Snow's next Oz book was delayed until 1949.
|The final "Famous Forty" Oz books|