Explorer Steve Backshall and wildlife presenter Michaela Strachan take viewers on a gripping journey into the heart of the Ice Age using stunning location filming from around the world. In this episode it's the battle of the early humans as Steve and Michaela uncover the David-and-Goliath story of Neanderthals versus Homo Sapiens as both species compete for survival. As the Ice Age comes to an end, we discover how the Great Thaw changed the planet as we know it. Through virtual production we witness the flooding of the Ice Age world and the birth of the modern age. And deep within the Arctic Circle Michaela uncovers the ultimate irony that global warming and the collapse of the Gulf Stream could trigger the next Ice Age.

Deep within the Arctic Circle, Michaela is in freezing Svalbard solving the puzzle of why the Ice Age started in the first place. Meanwhile Steve is in the UK discovering which ice age mega beasts used the UK as their stomping ground. Joined by Professor Danielle Schreve, she introduces Steve to the bones of mammoth, arctic foxes and even a massive Ice Age hyena. But Danielle has an even bigger discovery, and only now is she prepared to let the cameras in! She and her team uncovered the remains of almost a dozen ice age creatures all found in the same small cave near Plymouth. What could have killed these ice age titans – did they all fall victim to natural disaster or was one apex predator responsible for their deaths? It's an Ice Age murder mystery for Steve to solve.

The most famous predator of the ice age was the sabre-toothed cat and Michaela discovers why this fearsome creature was such an effective hunter. But as she examines this beast's skull and giant fangs, she discovers it had one major weakness… Could this have been the reason it went extinct?

In Sweden Steve gets under the skin of the mammoth, by investigating its DNA. With the help of world leading geneticist Professor Love Dalén, Steve explores why this titan of the Ice Age died out. But it seems the mammoth may not be extinct for long… Steve discovers a revolutionary gene editing technique that could bring them back from the dead.
 

In the epic conclusion to the Ice Age story, we discover how the Great Thaw brought the end of the Ice Age and changed the world as we know it. Steve Backshall and Michaela Strachan go in search of a long-lost land that once connected the UK to mainland Europe before the Ice Age ended. Steve dives beneath the waves hunting for signs that the sea floor was once land and the thriving heart of Europe. Back on dry land, Michaela is on a hunt to find out more about this ancient land and wants to know how it flooded. She discovers that, less than 10,000 years ago, there was a natural disaster of epic proportions that helped form the North Sea and cut the UK off from Europe permanently. But this disaster may have been the catalyst for humans to develop further. Steve explores how early humans quickly adapted to their newly flooded world by developing watercraft unlike any we see on the rivers today. Meanwhile, deep in the Arctic, Michaela is working with the British Antarctic Survey as they drill for ice cores from a remote glacier. The ice they recover could reveal how the climate is changing around the globe. Bizarrely, Michaela discovers how a warming world may actually create the perfect conditions to trigger a new Ice Age. But if the world were plunged into the deep freeze again, how might we as a species cope? Steve goes in search of answers and meets a survival expert who understands the terrible dangers we may face. And Michaela visits a site in the Arctic where they're preparing for a means for humanity to survive after an apocalyptic event.

It was during the Ice Age that humanity as we know it was forged. Two rival species competed until only one was left standing. Steve Backshall and Michaela Strachan travel the world to discover how Neanderthals and Homo sapiens survived at a time of brutal environmental change and uncover why we, Homo sapiens, survived while the Neanderthals were wiped off the face of the Earth. Steve heads to southern Germany, which is a hotbed of early human discoveries. In the freezing temperatures of the snow-lined valleys, Steve throws himself into Ice Age life, exploring how early humans evaded the mighty Ice Age predators such as the supersized cave bears and giant hyenas that stalked the freezing wastelands. In a battle against the elements and predators, Steve discovers how Neanderthals made fire in a surprisingly sophisticated way and crafted tools so sharp you could shave with them! Meanwhile, Michaela gets to grips with the differences between Neanderthals and Homo sapiens. At the prestigious Natural History Museum, she's able to see that Neanderthals were physically stronger than Homo sapiens and by looking at their skulls can see they even had bigger brains. So why then did we as a species survive and the Neanderthals did not? The answer could lie in how both species developed technology. Steve tests out the differences between how Neanderthals and Homo sapiens hunted mega-beasts like the woolly mammoth. He tries throwing Neanderthal spears, but discovers that Homo sapiens developed a better way to hunt. Meanwhile, Michaela uncovers how one invention, the humble sewing needle, gave Homo sapiens a huge advantage — why? But the biggest turning point in our species evolution came as the Ice Age thawed and a natural disaster loomed, one that threatened to wipe out the Neanderthals.