When a stranger calls at their New England farmhouse to inform Nancy and her brother Robert that they are the heirs of a British nobleman, and that a fortune can be theirs if they agree to move to the ancestral home of Benjamin House in London, it seems like all their childhood dreams have come true. But upon arrival, Nancy is soon homesick - while Robert nearly loses his life in an 'accident'. Then there's the mysterious ancient riddle connected with the house that could point the way to hidden treasure...