In Crumbleton, muffins are serious business. When the town's prized Golden Muffin Trophy vanishes days before the annual Muffin Mania festival, amateur sleuth and bumbling baker Penelope "Penny" Pumpernickel takes on the case. Armed with her questionable baking skills, a loyal but dimwitted dachshund named Crumpet, and a knack for tripping over clues, Penny unravels a web of small-town secrets, rival bakers, and a shady muffin mafia. With suspects ranging from a melodramatic mayor to a suspiciously cheerful yoga instructor, Penny must solve the mystery before the festival flops and her bakery, The Crusty Crumb, goes under.