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).

NASA's brand-new Mars rover is on the hunt for alien life, and with the help of cutting-edge engineering, scientists embark on a search for fossilized remains, which might prove the Red Planet was once home to a vast ocean and extraterrestrial life. Perseverance carries seven scientific instruments to study the Martian surface at Jezero crater. It carries several cameras and two microphones. The rover is accompanied by the helicopter Ingenuity, which will help Perseverance to scout for locations to study.

Widespread dietary changes are needed if we’re to combat the range of health problems associated with obesity and the environmental damage caused by industrial farming. Switching to a vegan diet is a potential solution, but selling the idea to the meat-eaters around the world is a tricky proposition.

Professor Simon Schaffer presents the amazing and untold story of automata - extraordinary clockwork machines designed hundreds of years ago to mimic and recreate life. The film brings the past to life in vivid detail as we see how and why these masterpieces were built. Travelling around Europe, Simon uncovers the history of these machines and shows us some of the most spectacular examples, from an entire working automaton city to a small boy who can be programmed to write and even a device that can play chess". All the machines Simon visits show a level of technical sophistication and ambition that still amazes today. As well as the automata, Simon explains in great detail the world in which they were made - the hardship of the workers who built them, their role in global trade and the industrial revolution and the eccentric designers who dreamt them up. Finally, Simon reveals that to us that these long-forgotten marriages of art and engineering are actually the ancestors of many of our most loved modern technologies, from recorded music to the cinema and much of the digital world.

The second episode tells the story of the trial of Hermann Goering, Hitler's charismatic and ruthless second-in-command. On trial for his life at Nuremberg, the unrepentant Reich Marshal turned the tables on the Allies. So much so that Chief Prosecutor Justice Robert Jackson began to wish the Allies had followed Churchill's suggestion and shot the leading Nazis out of hand. This documentary drama traces the behind-the-scenes story of Goering's attempt to re-ignite Nazism from the courtroom.

New Zealand - 850 years ago New Zealand was the last major land mass to be discovered and colonised by humans. A mere 850 years ago, Polynesian seafarers arrived in a land with no terrestrial mammals. New Zealand was a land of birds, and its avian rulers were giants: huge herbivorous moas were hunted by Haast's eagle - the largest eagle the world has ever seen. But within the space of only 100-400 years, the eagle, all the moas and over 20 other species of birds were gone. Had mankind become the monster?