In the mining town of Prosperity, Arizona, a truck transporting chemical raw materials had an accident and dumped toxic waste into the local river. Thousands of spiders from the spider breeder in the town were contaminated and became huge in size, entering the abandoned mines in batches to live and reproduce. Mike (Scott Terra) the son of the town sheriff Sam Parker (Kari Wührer) discovered a huge spider leg and suspected that the spider breeder was killed, but his mother Sam did not listen to his son's explanation. Chris McComock (David Arquette), the son of the town's mine owner, returned from the town council and opposed the mayor's suggestion to sell the mine. Chris still had feelings for Sam, but he did not have the courage to express his feelings to the beauty. Mike showed the giant spider leg to Chris, who was still skeptical. At the same time, the giant spiders in the mine began to attack animals in the town, and then humans. The communication system was also destroyed by the "eight-legged monster", and the lives of the people in the town were in danger...