18x14 - Doctor Who

The Doctor and Romana are escorted to the tower to meet the royal leaders, hoping they can find answers to why this society evolves backwards. The Doctor recognizes the tower as an old Earth spaceship, and further finds that the old fuel tanks, far from empty, are full - but with blood. Meanwhile, Councilor Aukon senses intelligence in Adric and selects him to be the their first "Chosen One."