Seventeen-year-old Cassandra Mortmain and her family live in a beautiful, ramshackle castle - but sadly that's not quite as exciting as it sounds when you're having to use the barn door as a kitchen table, and new clothes are literally made out of old curtains . . . Determined to forge her own path, Cassandra practices her writing skills by keeping a diary - observing the eccentric comings and goings of her beloved-but exasperating family, and pondering what life may have in store for her. But things are about to get delightfully more dramatic with the arrival of two glamorous Americans - and soon the Mortmain's lives will never be the same again.