At eccentric Aunt Lucy's house in Yorkshire, England, fourteen-year-old aviatrix Emmaline Cayley; 'indestructible' co-pilot Robert 'Rubberbones' Burns; and Princess Purnah of Chilgrit, recent escapee from St. Grimelda's School for Young Ladies, are merrily jumping off the roof at the request of their new tutor, the nutty American inventor Professor Bellbuckle. But trouble is on the horizon for this madcap crew: St Grimelda's wants Purnah back, the government wants her to return to the school and, worst of all, a terrifying master criminal known as The Faceless Fiend wants to kidnap her!