Mark your calendars for this Sunday (June 21st) when the 13 part BBC One series "Merlin" comes to NBC at 8 PM EDT. Not only is this the first British drama to air in the US since the New Avengers in the 1970's, but NBC has announced that it will be airing a sneak preview ofHarry Potter and the Half-Blood Prince during the premiere. According to the NBC website, "The series “updates the story of the infamous sorcerer of Arthurian legend for a new audience.” On "Merlin," magic is illegal in Camelot, a rule that is enforced by young Prince Arthur’s father, Uther Pendragon. This law proves problematic for Merlin, a young sorcerer who arrives in Camelot and wastes no time in making enemies. But Merlin soon realizes that he must use his magic both to survive and to protect the future King Arthur."