 Set in the year 1992, ten years after a limited nuclear war as destroyed most of the USA, scientist Paul Dean has developed a new form of leach-like parasite which can grow to large portions every time it eats. Then, evil government agents storm his lab and he s forced to flee deep in the nearby desert and persued by a "merchant" (government agent) intent on reclaiming the last two parasites Paul has. The first is in a silver container, the other is in Paul s abdomen. Paul seeks shelter in a small desert town populated by scavengers which threaten his work, while one local girl, Patrica Wells, forms an alliance with Paul to help him find a way to kill the parasite within him without killing himself, as well as find a way to kill the other one which gets loose and will soon multiply into many thousands unless killed soon.