The Arctic is the harshest environment on Earth: little food grows, it's dark for months on end, and temperatures stay well below freezing for much of the year. Yet four million people manage to survive here. Human Planet tells remarkable stories of extraordinary people who make their homes in nature's deep freeze. In springtime, Amos and Karl-Frederik set out across the sea ice with their dogs to catch a real-life sea monster: a Greenland shark! Inuit mussel-gatherers venture underneath the sea ice at low tide for a perilous race against time as they gather their food. And the children of Churchill, Manitoba, set out on the most dangerous trick or treating Halloween in the world: they risk coming face-to-face with deadly polar bears on the streets of their town. Who'll get the tastiest snack?

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.

Do other worlds tremble and heave with geological life? On Mars, we found a volcano to dwarf Mount Everest. On the moons of the giants our understanding of volcanoes was changed forever.

This episode discusses the human exploration of Antarctica, in particular the mission led by Captain Robert Falcon Scott, whose team died on the way back from the South Pole. It shows the scientific work in the modern human bases in Antarctica, especially Mawson Base and its observation of Adelie Penguins (partially through tracking devices). The second half of the episode describes how the series was made. Most crucial was of course the camera work. To get access to the wildlife of the sea, for example, boats, divers, suspended capsules and remotely controlled cameras mounted on inflatables were used. Particularly dangerous to divers were Leopard Seals and other predators. The film concludes that although working in Antarctica is now much easier than during the early days of exploration, human footsteps on the continent are still exceedingly rare in part because of international treaties prohibiting industrial exploitation.

Are the wealthy just born in the right place at the right time? Are the poor victims of a system designed to keep them down? Or do physics and biology determine who is rich and who is poor? Throughout history, distribution of wealth is governed by hidden forces: DNA, environmental stress, patterns of human migration and even the laws of thermodynamics! Nature seems to demand winners and losers in life. But does this mean greed is king, and the rich can take what they want? Or is cooperation – between microorganisms, monkeys, and humans – more essential to survival of a species?

Humanity’s potential seems limitless. But could we become as powerful as God? Scientific breakthroughs grant our species seemingly divine abilities. Biologists tinkering with DNA are figuring out ways to grow new life forms, while neuroscientists try to create artificial consciousness. Statisticians around the world are using big data to predict the future and computer scientists have discovered a "God algorithm" that could solve any global problem in an instant. But to truly become God, we not only have to be all knowing, but all being. Quantum physicists are figuring out how to teleport matter at the speed of light!