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
The Master (Doctor Who) believe he is needed for a great purpose (implied to be the Time War) — the event had been referenced in "The Sound of Drums". Chris Finney plays a character named 'Keith Potter' in the story "The End of the Line" from the audio anthology "" , who is later revealed to be an avatar under the control of the Master. The Master, played by Geoffrey Beevers, makes a cameo appearance in series 10 of the Doctor Who spin-off Jago & Litefoot, and later featured as the main villain for the 11th series. To commemorate the Master's forty-fifth anniversary, Big