"In this final episode Dawkins examines why Darwin's theory remains one of the most controversial ideas in history.
As Darwin set out on the voyage on the Beagle he still believed that god created the world and everything in it. But the evidence he discovered - fossils, patterns of anatomical resemblance, startling similarities of embryos and domestic breeding - demonstrated the truth: that all life forms vary and that some are more likely to reproduce, passing variations on. His wife Emma, however, was deeply religious and Darwin never criticised religion in public but he believed that "science would bring about a gradual illumination of minds.
Dawkins travels to meet an old friend, Dan Dennett, who shares many of his own beliefs, to answer the question Darwin himself was confronted with: how can we find solace in a godless world?"