Episode 3: Autumn. Yellowstone's autumn is when elk move down from the mountains, and beavers repair their dams in preparation for the fast approaching winter.
Episode 1: Winter. In winter, Yellowstone National Park is frozen solid, buried by snow as deep as a house. While the herds of elk and bison are gradually weakened by the cold, the wolves grow stronger.
Episode 2: Summer. As the snow melts, the extent of Yellowstone is revealed. Grizzly bears teach their young how to hunt fish and when to move out through the valleys and up into the peaks.