Leaving their son, Chris (Daniel Holzman), with a family friend (William Wellman Jr.), Frank (John P. Ryan) and Lenore Davis (Sharon Farrell) head to the hospital for the birth of their second child -- which turns out to be a mutant who kills many doctors and nurses as it escapes. Convinced his monstrous son must be destroyed, Frank ignores Lenore and Chris' pleas and tries to destroy the freakish progeny, unaware that the infant may be the blameless product of an experimental drug gone wrong.