Dr Thomas Dixon delves into the BBC's archive to explore the troubled relationship between religion and science. From the creationists of America to the physicists of the Large Hadron Collider, he traces the expansion of scientific knowledge and asks whether there is still room for God in the modern world. He looks at what happens when new scientific discoveries start to explain events that were once seen as the workings of God, and explains how some of our most famous scientists have seen God in the grandest laws of the universe. Finally, he finds intriguing evidence from brain science which hints that belief in God is here to stay.

Nick Yarris, a convicted murderer who has spent 23 years on Death Row and was released in 2004 when DNA evidence proved he was innocent of the crime, tells his story. In a non-linear structure, he reveals his early life, youthful transgressions, arrest, and time on death row, with several twists and turns. This gripping documentary reels you in, closer and closer, finally playing its hand in the closing moments.

To recruit actors for his rehearsals, Nathan opens an acting studio in Los Angeles, teaching 'the Fielder Method', which involves covertly observing and imitating unaware subjects. Feeling insecure about his own performance, Nathan reenacts the class with actors and a fake Nathan as the teacher while the real Nathan plays the role of Thomas, a student. Nathan makes his students immerse themselves in other people's lives while he immerses himself in Thomas's life, even living in Thomas's home.
Nathan returns to Oregon, where his 'son', Adam, is now a teenager. Nathan and Joshua, the actor playing Adam, decide that Adam should lash out due to resentment of his absentee father and develop a drug problem, a situation that mirrors Angela's own past. Adam suffers an overdose and is tended to by emergency responders played by Thomas and another Fielder Method graduate. After he runs away from home, the 15-year-old Adam reverts to a 6-year-old since Nathan plans to relive his son's earlier years.

Morgan Freeman travels the world to study the cycles of war and peace. From the ritualized combat of the sacred Tinku festival in Bolivia to Rwanda's post-genocide reconciliation program, this episode deals with humanity's enormous capacity for violence and the endless pursuit of harmony. Conflict can drive innovation, but is war necessary?

Atheist and scientist Richard Dawkins visits England, America and Israel interveiwing prominant people of faith; Islamic, Hasidic Jews, and the new Christian sects popping up throughout the world, and expressing his view of the extent to which this fanaticism has degraded our civilisation, and will continue to degrade it. "The God Delusion" explores the unproven beliefs that are treated as factual by many religions and the extremes to which some followers have taken them. Dawkins opens the programme by describing the "would-be murderers ... who want to kill you and me, and themselves, because they're motivated by what they think is the highest ideal." Dawkins argues that "the process of non-thinking called faith" is not a way of understanding the world, but instead stands in fundamental opposition to modern science and the scientific method, and is divisive and dangerous.

Grasslands feed the world. Over thousands of years, we humans have learned to grow grains on the grasslands and domesticate the creatures that live there. Our success has propelled our population to almost seven billion people. But this episode reveals that, even today, life in the 'Garden of Eden' isn't always rosy. We walk with the Dorobo people of Kenya as they bravely attempt to scare off a pride of hungry lions from their freshly caught kill. We gallop across the Steppe with extraordinary Mongolian horsemen who were 'born in the saddle'. And in a perfect partnership with nature built up over generations Maasai children must literally talk to the birds! The honeyguide leads them to find sweet treats, but they'll have to repay the favour.