Toto and the Cats of Oz is a 2013 Oz book written by Robin Hess.
Description[]
The cats of Oz, led by the mysterious and wicked black cat named Joom, are trying to take over all of Oz. Toto has disappeared and Dorothy Gale is beside herself with worry. Impervious to the Wizard's magic, the cats successfully conquer the Emerald City. Ozma and Glinda, making a last stand in Glinda's Ruby Palace, have called together all the friendly magic workers from all over, even some from beyond the Deadly Desert. But how can they stop the cats if they are impervious to magic? How can they save Toto and Oz?