Paradise Towers two elderly residents ("rezzies") live. Tilda and Tabby explain that all the able-bodied men left the Towers to fight a war, leaving behind only children and the elderly. The only other man still loose in the Towers is Pex, a would-be hero, who appoints himself Mel's guardian. At the Caretaker control centre, the Doctor meets the Chief Caretaker, who greets him as the Great Architect, designer of Paradise Towers, and then promptly calls for him to be killed The Doctor cites an imaginary rule from the Caretakers' manual, confusing them enough to make his escape. Mel and Pex meanwhile have
Eleventh Doctor mystery of "the Impossible Girl". The Doctor eventually gets his answer in "The Name of the Doctor" when he is forced by the Great Intelligence to go to Trenzalore, revealed to be planet on which the Doctor will die. Within the Doctor's tomb, the Great Intelligence uses the dead Doctor's remnants—his disembodied "timestream"—to spread himself across the Doctor's history, turning his victories into defeats. Clara pursues him and is scattered throughout the Doctor's timeline creating Oswin Oswald and Clara Oswin Oswald among numerous other incarnations who undo the Great Intelligence's work. The Doctor has a mournful conversation with River's apparition,