Professor Alice Roberts begins her Ice Age odyssey in North America, the hunting ground of the saber-toothed cat. The continent was half covered by ice that was up to two miles thick. Yet this frozen land also boasted the most impressive cast of Ice Age giants in the world, such as the grizzly bear-sized Shasta ground sloth and the glyptodon, surely the weirdest mammal that ever lived.

Professor Alice Roberts continues her Ice Age adventure by exploring the parts of the Northern Hemisphere hit hardest by the cold: Europe and Siberia. There she discovers that cave lions and cave bears, two ancient creatures that would dwarf their modern-day relatives, fought to the death for food. Yet Alice discovers that, for woolly rhinos and woolly mammoths, the Ice Age created a bounty.

As the Ice Age ended and the world warmed up again, many species became extinct. Professor Alice Roberts tries to find out why mammoths, woolly rhinos, saber-toothed cats, giant ground sloths and glyptodonts finally vanished. Mastodons were turning on mastodons as food grew scarce while woolly rhinos were faced with an unexpected problem due to the changing climate.