When the final season of the highest-rated drama in PBS history opens, it's 1925. Lady Mary runs theestate, and Lady Edith manages the magazine she inherited from Michael Gregson. Tom Bransonhas left for Boston, newlyweds Lady Rose and Atticus Aldridge are trying their luck in Jazz Age NewYork, and Anna Bates faces a murder charge. What of the Dowager Countess of Grantham, indeliblyportrayed by Maggie Smith? Downton creator Julian Fellowes has vowed, "Maggie will never die!"9 episodes, 8 1/2 hrs, 3 DVD or Blu-ray discs.