The drama in Children of the Corn IV begins when a young medical student takes a semester off to come home and take care of her sick mother. The mother is having recurring nightmares - lurid, sweaty dreams filled with feverish children killing her. At the same time, the body of a child dressed as an old-fashioned preacher is found by a farmer in his well. The body comes to life and kills the farmer, unleashing a plague of fevers and dreams that sweep through the children of the small Nebraska town. Then, all at once, the symptoms vanish, and the children appear to get better. Then everything gets worse.
The children in town begin to listen to the words of the child preacher, whose name is Josiah. Josiah's flock begins to show strange signs of decay, with teeth falling out as the children refuse to answer to their given names. Instead they all take on the names and identities of children from generations ago, now all dead. This sets the scene for a grisly showdown between the remaining adults, who have uncovered their dark powers under Josiah's command, and the child preacher and his minions. In the end Josiah is destroyed, the children mostly return to normal, and the survivors of this latest, bloody chapter decide to live the rest of their lives somewhere that isn't in Nebraska.