Once it gets inside you, it will do anything to get out!
In the near future, an atomic disaster has reduced the world to poverty. Instead of a government, America is run by an organization called the Merchants, who exploit the degenerate remains of society. In order to keep control of the populace, the Merchants force Dr. Paul Dean (Robert Glaudini) to create a new life form, a parasite that feeds on its host. Realizing the deadly potential of such a being, Dean escapes the Merchants with the parasite, infecting himself in the process. Now on the run, he travels from town to town, studying the parasite so that he can find a way to destroy it, all the while keeping one step ahead of a Merchant named Wolf who is hunting for him. While resting in a desert town, he is attacked by a gang of hooligans led by Ricus, a former slave of the Merchants. The gang steals silver canister containing the parasite, not realizing what it is, and it escapes and infects one of the members. Meanwhile, Paul befriends a pretty young lemon grower named Patricia Wells, who promises to help him destroy the escaped parasite. Ricus, trying to save the life of his friend, comes to Paul for help, only to be confronted by Wolf. Patricia, Paul, and Ricus manage to evade Wolf, but when they return, the parasite has spread to another member and grown into a fleshy worm with a mouthful of deadly teeth. Ricus becomes a turncoat and attempts to help, but ends up getting killed by Wolf. A friendly diner owner, named Collins, comes to aid the group. After Patricia helps kill the parasite in Paul, which they electrocute, the worm attacks Wolf who is then blown up by Patricia, Paul, and Collins.