Twins Edgar and Ellen, whose exploits have been reported in books from "Rare Beasts" to "Nod's Limbs," present a how-to book for aspiring members of their newly-established League of Mischievists.

Mischievous twins Edgar and Ellen must thwart the plan of Mayor Knightleigh's wife to renovate their crumbling house, but Edgar has to plot alone when a hairy, one-eyed creature turns Ellen into a model of proper behavior