This is the 35th Oz book, preceded by The Wonder City of Oz, and followed by Lucky Bucky in Oz. The Wizard creates Scalawagons, intelligent cars that can also fly. He makes Tik-Tok superintendent of the Scalawagons Factory, but the mechanical man runs down. Bell Snickle, a mysterious creature, takes advantage of Tik-Tok's condition by filling the scalawagons with "flabber-gas". Can the Wizard and all his Oz friends round up the Scalawagons before they become irretrievably lost?