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
Doctor Who be revealed; this is explored further in "The Name of the Doctor" (2013), when River Song speaking his name allows the Great Intelligence to enter his tomb, and in "The Time of the Doctor" (2013) where speaking his true name becomes the signal by which the Time Lords would know they can safely return to the universe. The companion figure – generally a human – has been a constant feature in "Doctor Who" since the programme's inception in 1963. One of the roles of the companion is to be a reminder for the Doctor's "moral duty". The Doctor's first companions