Dramatised documentary in which Andrew Marr explains how Edinburgh changed from a squalid provincial city into a beacon of intellectual thought, led by the brilliance of the philosopher David Hume and the father of economics, Adam Smith. Their enlightened ideas opened up the eyes of the people across the world, arguing for a progressive and tolerant society with freedom of speech, freedom of thought, and freedom of action. Their ideas are just as relevant today as they were over 250 years ago.