The Adventures of Sir Lancelot

The Ugly Duckling (1x25)

Air date: Mar 16, 1957

While on a visit to castle Lamorack, Sir Lancelot and Merlin try to help their host when he receives a note threatening his daughter's life. Merlin learns that the note is false, and written by the girl herself in a bid for attention. Later the girl disappears. Another notes arrives and this time it's genuine.