The depletion of the earth's ozone layer causes animals above the altitude of 5000 feet to begin attacking humans. A group of hikers led by Steve Buckner (Christophe George) are trapped in the military quarantine zone, and now must fight there way a cross the dangerous terrain to safety. Complicating matters is one of the hikers Paul Jenson (Leslie Nielsen), a boorish advertising executive, decides that he should take charge and go a separate way.