A young man and his father go hunting in a mountain area with forests somewhere in the American Midwest. Before they get to hunt anything, which the son is not to eager to do anyway, both of them get killed by strange flying jellyfish-like creatures which hit them and penetrate their skin with sharp-tipped tentacles. Some time later, four young teenagers, Tom, Greg, Beth and Sandy, go on a hike in the same area, ignoring the warnings of Joe Taylor, a local truck stop owner. A group of cub scouts is also in the area; their leader is also killed by the alien creatures, while his cubs run into an unidentified humanoid and flee.