The Children of Green Knowe was adapted from the first of Lucy M. Boston’s six books about the fictional manor house, Green Knowe. It concerns the visit of a young boy, Toseland (Alec Christie), to the magical house, Green Knowe. The house is tremendously old, dating from the Norman Conquest, and has been continually inhabited by Toseland’s ancestors, the d’Aulneaux family, later called Oldknowe or Oldknow. Toseland crosses floodwaters by night to reach the house, to spend the Christmas holidays with his great-grandmother, Linnet Oldknow (Daphne Oxenford), who addresses him as “Tolly”.
Tolly explores the rich history of his family, which pervades the house like magic. He begins to encounter what appear to be the spirits of three of his forebears—an earlier Toseland – nicknamed Toby (Graham McGrath), Alexander (James Trevelyan), and an earlier Linnet (Polly Maberly)—who lived in the reign of Charles II. These meetings are for the most part not frightening to Tolly; they continually reinforce his sense of belonging that the house engenders. In the evenings, Mrs. Oldknow (whom Tolly calls “Granny”) entertains Tolly with stories about the house and those who lived there. Surrounded by the rivers and the floodwater, sealed within its ancient walls, Green Knowe is a sanctuary of peace and stability in a world of unnerving change