在冰河时期史诗故事的终章中，我们探索大融化如何终结了冰河时期，彻底改变了我们所知的世界。Steve Backshall 与Michaela Strachan 寻找失落大陆的征途——这片神秘土地曾在冰河时期结束前连接英国与欧洲大陆。史提夫将深潜海底，搜寻海床曾为陆地及欧洲繁荣中心的证据。然而当史提夫潜入深海时，他的发现远超预期。

回到陆地，Michaela深入调查这片古老大陆的秘密，试图解开其沉没之谜。她发现在距今不足一万年前，一场史无前例的天灾变塑造了北海，永久分割了英国与欧洲。这场浩劫或许正是推动早期人类文明跃进的关键转折点。
Steve深入研究早期人类如何快速适应新的水世界，创造出异于今日的船舶的独特水上载具。当史提夫亲自测试这些远古船只时，其性能表现令他震惊。
同一时间，在北极，Michaela与英国南极调查局携手合作，从偏远冰川深处钻取珍贵的冰芯。这些冰层样本将揭示全球气候变迁的关键讯息。令人惊异的是，Michaela发现气候暖化竟可能是触发新冰河时期的理想条件。

倘若地球再度坠入冰封世界，人类物种将如何求存？Steve展开探索之旅，与一位深谙末日威胁的生存专家会面；Michaela则会带我们造访北极的末日准备基地，一座位于冰层深处，专为确保人类在末世浩劫后的延续而建地下堡垒。

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 will dive beneath the waves hunting for signs that the sea floor was once land and the thriving hearty of Europe. But when Steve goes deep beneath the waves, he finds more than he bargained for…
 
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 early 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. As Steve tests out these ancient boats he’s shocked by the results.   
 
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 are preparing for doomsday. She’s at an underground bunker beneath the ice that is working on ensuring a means for humanity to survive after an apocalyptic event.