The sleepy desert town of Prosperity, Arizona is being menaced by giant arachnids that have mutated through exposure to toxic waste. The local sheriff and her teenage daughter work to prevent a complete takeover by the bloodthirsty spiders, getting valuable help from Prosperity's prodigal son, who's just returned to his embattled hometown.

Joe Fisk, a street smart kid, is sentenced to hard labor in a state youth reformatory. He meets Lisa, a beautiful sheltered young girl, studying at a nearby convent. It's love at first sight and when passions ignite, nothing can keep them apart--not even the law.

A documentary film crew headed by anthropologist Steve Cale and director Terri Flores travel down the Amazon River in search of a mysterious Indian tribe. On their way the save a man from a sinking boat. He offers to help in their search for the tribe, but he is actually a snake-hunter looking for the legendary Anaconda snake. When an accident leaves Cale unconscious, Sarone takes charge of the boat, leaving the rest of the crew in grave danger.