It's autumn, and Covenly residents are gathering at the annual fall fair. The three Weird Sisters-Hildegurp, Glubbifer, and Yuckmina-are running a Flying Broom ride for the town's kids and nine-year-old Jessica Nibley is overseeing the petting zoo nearby. Suddenly, a prized show chicken goes missing and there's a new mystery to solve. Suspecting fowl play, the four friends team up to find the hapless hen in a madcap hunt that involves an enchanted roller coaster, a frog in a top hat, and a sticky trail of goo. As they sleuth, the sisters also discover some unfortunate and unintended consequences of their magic, bringing about a gentle lesson in apologizing.