West Yorkshire, 1904. A young Norland nanny named Ruby May is assigned to a remote estate to care for the children of a wealthy couple from a powerful mill dynasty. Ruby hopes it will be the fresh start she needs. Yet when she arrives at Hardcastle House, she finds the staff is hostile to her, and the lady of the house, Mrs. Lilian England, cold and withdrawn. The only person who seems solicitous is the gentleman of the house, Charles England, but in an uncomfortable way. It doesn't take long for Ruby to sense all is not as it seems, that the house holds a dark secret. But there's no such thing as the perfect family-Ruby herself should know. And she would be the last person to pry; after all, she is holding a dark secret of her own.