Jonathan Miller traces the history of atheism across three episodes, starting at the site of the fallen Twin Towers, where he considers what 9/11 means for religious belief and talks with Arthur Miller and philosopher Colin McGinn. From there he goes back to Ancient Greece hunting for the first recorded unbelievers, then forward to the fifteenth and sixteenth centuries, arguing that splits within the Church did more to open space for doubt than any scientific discovery of the era. A stop in Paris covers Baron D'Holbach and the real danger of atheism in eighteenth-century France. The final episode follows Thomas Paine, the geological and Darwinian evidence that undercut biblical literalism, and Freud's claim that religion functions as a thought disorder. Miller closes on his own reasons for making the series, weighing death and the religious violence of the twenty-first century. Throughout, he works as both host and interviewer, asking why belief in gods and magic has been so persistent and what actually chips away at it.