Science, reason and democracy. The Age of Enlightenment began three hundred years ago. It brought greater freedom and progress and paved the way for modern thought. Today, in the 21st century, does the Enlightenment still matter? The documentary looks deeply at historic Enlightenment thinkers Denis Diderot, Olympe de Gouges, Thomas Jefferson and Immanuel Kant. Then, it puts their ideas to the test in the modern world. How much information does humankind need? How can we distinguish between true and false information? How can truth be defended against governments, dictators, and intelligence agencies that spread misinformation and manipulate evidence? And how do we come by real knowledge?