Episode one focuses on The Rockies: the spine of North America, running for 3,000 miles from the southern United States to the edge of the frozen north of Canada.This beautiful wilderness of snow-capped peaks and hidden valleys is the home to some of the most revered animals on the planet: the grizzly bear, wolf, bison and elk. As the cougar hunt in abandoned ranches, the wolverines search the deep snow for food and grizzly bears hunt in the high mountain meadows, we follow these elusive winter specialists.