All hell breaks loose when a 15-ft grizzly bear, reacting to the slaughter of her cub by poachers, seeks revenge and kills anyone that gets in her way. In the 3 days before the major concert taking place in Yellowstone National Park, the gigantic grizzly has brutally attacked campers Ron (George Clooney), Tina (Laura Dern) and Lance (Charlie Sheen), poachers and a park ranger. The terror doesn’t end there as the giant grizzly bear finds its way to the concert grounds to go on a killing spree.