An American boy and girl, spending six months in Kenya with their scientist parents adopt a cheetah, only to realize that they must set it loose so that it can learn to hunt and be free. However, when the animal is captured by poachers planning to race it against greyhounds, the two city kids, together with a young African goat herder they befriended, head off into the wild to rescue the cheetah.

Investigating the mysterious deaths of a number of farm animals, vet Rack Hansen discovers that his town lies in the path of hordes of migrating tarantulas. Before he can take action, the streets are overrun by killer spiders, trapping a small group of townsfolk in a remote hotel.

"Genius" accidentally invents "goo" which causes living things to rapidly grow to an enormous size. Seeing an opportunity to get rich, some delinquent teenagers steal the "goo" and, as a result of a sophomoric dare, consume it themselves and become thirty feet tall. They then take over control of the town by kidnapping the sheriff's daughter and dancing suggestively.