Margatroyd is a witch with a personality--sly, hot-tempered, generous; she impulsively named herself and her cat Hornsbydale after two property agents. Ten-year-old Judy finds them in the shrubbery outside her house, somehow qualities to absorb a little magic. She even manages to contribute some in the form of a dragon, Fizz, who used to live on an old tray of her mother's, but before that was at the right hand of the great ancient wizard of China, Fly-by-the-Moon. When Fizz has regained much of his former magic, he and Judy go to Eternity where he stays with his master while Judy returns home. A lively year with magic in the back yard; dialogue, description and idiosyncrasies to amuse; an undercover battle between black and white magic to move it along.