The Hidden House

When orphans Anabelle Bentford and Nathaniel Waterstone discover a mysterious palace in the countryside near their cottage, they are warned by their guardian, Nathaniel's older sister Bessie, to never go near it again. Nathaniel listens, but Anabelle, being curious as she is, does not. She enters the seemingly uninhabited palace later that night and, while exploring it, finds a door that leads to a secret passage to a hidden house far below ground. This lavish mansion, she discovers, is inhabited by three peculiar children who have not been permitted to leave it in seven years for reasons they Anabelle is shocked to hear. She soon takes it upon herself to free them from their restrictive home without being discovered by someone who is determined to keep them there at all costs. But before Anabelle can do this, she must first convince the children that they should leave their sheltered environment for the outside world, which might be the greatest challenge of all.