Einhorn features characters from both his Oz novels, Paradox in Oz (1999) and The Living House of Oz (2005), in "Unauthorized Magic." In the story, Dr. Majestico (from the first book) has appeared in Oz in the present time; in the Munchkin Country, he is busily but unsuccessfully trying to explode his house, at the bidding of Tempus the time-travelling Parrot-Ox (also from the first book). The problem involves the traditional paradox of the irresistible force versus the immovable object.
Dr. Majestico's neighbor happens to be Buddy, the boy protagonist of Living House. Ozma, Glinda, and Omby Amby come to see the Doctor, because his activities violate the general prohibition against magic in Oz. This concerns Buddy, since his mother is another, though secret, practitioner of unauthorized magic.