A poacher hunting for grizzly bears in Yellowstone National Park slaughters a cub and wounds its mother. Bent on revenge, the giant grizzly attacks anyone who crosses her path, including campers Ron (George Clooney), Tina (Laura Dern) and Lance (Charlie Sheen). As the park prepares for a massive rock concert, the ferocious grizzly embarks on a terrifying killing spree, leaving blood and destruction in her wake.