Corinna Stonewall is 15 years old and an orphan. She is also Rhysbridge Foundling Home’s Folk Keeper – a difficult and dangerous job which consists of looking after and controlling ‘the Folk’ – spiteful, maverick, savage creatures who live in the cellar and will only be prevented from spoiling the milk, terrifying the livestock and other disruptions by gifts of cream, salt pork and other luxuries. But there are many questions about Corinna. Who are her parents? Why does her hair grow two inches a night? Why does she feel drawn to the sea and long for the sweet taste of fish?