Yellowstone, the world's first national park is no ordinary wilderness, it is a lost world of vast plains and endless forests defended on all sides by towering mountains. Home to America's last great bison herds, the grizzly bear and the wolf - it is the most extensive thermal area on earth with more than 10,000 boiling springs, fumaroles and bubbling mud pots and more geysers than the rest of the world put together. It's these strange natural wonders that first made Yellowstone famous and still make it unique today. This landmark series reveals the grandeur of this fascinating place as its animals struggle to survive over the course of the vividly changing seasons. Join the charismatic cast of Yellowstone's wildlife as they turn to face the extreme challenges of the seasons and discover just what it takes to brave temperatures 40 degrees below zero, to live through raging forest fires or to fight to the death for the right to breed. The daily struggles of the wildlife are intimately linked to Yellowstone's greatest secret: that sleeping right beneath the snow is arguably the world's largest volcano. The fate of everything in this extraordinary wilderness is in the hands of forces more powerful than we can possibly imagine.