9 year old Caroline Sweet has a strange yet spectacular life: she lives in a beautiful country park with her mum, where she never has to go to school and can play in her special walled garden. But her happiness is threatened when her mum dies just a month before her birthday. There she is sent to live with her wealthy godfather in London where his wife doesn't want Caroline at all. Will she ever move on after her mum's sudden death? What secrets will she uncover along the way?