Bettany begins her journey in the city of Trier on the banks of the Mosel in Germany. It was here on the 5 May 1818 that Karl Marx, one of the most important philosophers of the 20th century was born.

Bettany searches to clarify the beliefs of a man whose work is possibly the most devastatingly manipulated and misinterpreted in philosophical history. The 19th century philosopher, Friedrich Nietzsche was one of the most brilliant and dangerous minds of the century.

Bettany travels to Vienna to discover that when Sigmund Freud first visited the city, it was one of political and economic turbulence. Freud was dubbed the "Father of psychoanalysis": his work changed the landscape of how we understand the inner workings of the human mind.