Sagan discusses the story of the Heike crab and artificial selection of crabs resembling samurai warriors, as an opening into a larger discussion of evolution through natural selection (and the pitfalls of intelligent design). Among the topics are the development of life on the Cosmic Calendar and the Cambrian explosion; the function of DNA in growth; genetic replication, repairs, and mutation; the common biochemistry of terrestrial organisms; the creation of the molecules of life in the Miller-Urey experiment; and speculation on alien life (such as life in Jupiter's clouds). In the Cosmos Update ten years later, Sagan remarks on RNA also controlling chemical reactions and reproducing itself and the different roles of comets (potentially carrying organic molecules or causing the Cretaceous–Paleogene extinction event).

The series heads to the very frontiers of space and science to produce the definitive history of science fiction. What if our creations turn against us? The idea of creating life has fascinated society since the earliest days of science fiction. Robots transports viewers from the first steps of Frankenstein’s monster to the threat provided by the Terminator and the world of Cyberspace. Find out how Rutger Hauer created one of the greatest speeches in all of science fiction for Blade Runner. Discover from Kenny Baker the challenge of acting in Star Wars while inside the body of R2D2, and learn how Anthony Daniels was drawn to the role of C-3PO by concept art modeled closely on the robot from the silent classic Metropolis. The creators of the original Robocop describe how its hidden depths have given it enduring appeal and William Gibson reveals the origins of his seminal novel Neuromancer. From HAL in 2001: A Space Odyssey to the Cylons of the reimagined Battlestar Galactica and the world of The Matrix, this is a journey that asks – what does it mean to be human?

In the third episode we will see Europe by the 17th century taking over from the Middle East as the powerhouse of mathematical ideas. Great strides had been made in understanding the geometry of objects fixed in time and space. The race was on to discover the mathematics to describe objects in motion. This programme explores the work of Rene Descartes, Pierre Fermat, Isaac Newton, Leonard Euler and Carl Friedrich Gauss. Du Sautoy proceeds to describes René Descartes realisation that it was possible to describe curved lines as equations and thus link algebra and geometry. He talks with Henk J. M. Bos about Descartes. He shows how one of Pierre de Fermat’s theorems is now the basis for the codes that protect credit card transactions on the internet. He describes Isaac Newton’s development of math and physics crucial to understanding the behaviour of moving objects in engineering. He covers the Leibniz and Newton calculus controversy and the Bernoulli family. He further covers Leonhard Euler, the father of topology, and Gauss' invention of a new way of handling equations, modular arithmetic. The further contribution of Gauss to our understanding of how prime numbers are distributed is covered thus providing the platform for Bernhard Riemann's theories on prime numbers. In addition Riemann worked on the properties of objects, which he saw as manifolds that could exist in multi-dimensional space.

Angela Rippon and Dr Chris van Tulleken travel the world in search of the latest science that could help us all stay young and healthy for longer. They investigate the best ways to help both our bodies and brains age better. Up first is the body, and Angela travels to Germany to join a groundbreaking study which reveals the exercise that holds off ageing the most. Chris visits America to find out about the unexpected diet that can add years to our lives. And in Ecuador we meet a seventeen-year-old who looks like a child to discover how scientists hope he may hold the key to preventing the diseases of ageing.

Marcus Du Sautoy wants to find out how close we are to creating machines that can think like us: robots or computers that have artificial intelligence. His journey takes him to a strange and bizarre world where AI is now taking shape. Marcus meets two robots who are developing their own private language, and attempts to communicate to them. He discovers how a super computer beat humans at one of the toughest quiz shows on the planet, Jeopardy". And finds out if machines can have creativity and intuition like us. Marcus is worried that if machines can think like us, then he will be out of business. But his conclusion is that AI machines may surprise us with their own distinct way of thinking.

Everyone from the most simple-minded to the deepest thinking has pondered a question that strikes at the core of our existence: Is there life after death? What happens to the soul after we die? People who have had near-death experiences claim to have visited the other side before getting yanked back into consciousness. Now, some of the brightest minds in science are trying to understand how life can persist beyond the physical and what will it look like. It might be a quantum state based on the fundamental laws of the universe. Ultimately, it is a journey that struggles to decode the most complicated instrument in the universe: the human brain.