The film begins in 1918,<ref name="tonysloman"/> where a First World War widow, Mrs. Allen (Dorothy Alison) and her children, Lucy (Lynne Frederick), Jamie (Garry Miller) and baby Benjamin are reduced to living in a squalid, Camden Town Apartment. Just before Christmas, a mysterious old man, Mr. Frederick Percival Blunden (Laurence Naismith) visits the family, introducing himself as a representative of a firm of solicitors.<ref name="tonysloman"/> The family are told there is an opportunity to become the caretakers of a derelict country mansion in the Home Counties named Langley Park, which was gutted by fire years before, and is now in the charge of the solicitors. Mrs. Allen takes the post despite rumours that the house is haunted, her instructions to care for the property until such time as the heirs to the estate can be traced. The air of mystery deepens when the children see a portrait at the solicitors office of a man they believe to be Mr Blunden. The solicitor confirms this, but reveals that the portrait is of a man called Mr Blunden, who has been dead for a hundred years, the present Mr. Blunden being his great-grandson.