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.