Most of the action of Vineland involves the family of Zoyd Wheeler, who lives near the town of Vineland and who collects mental disability checks for which he demonstrates his qualifications annually by jumping through the plate glass windows of a local bar. Zoyd has a daughter, Prairie, whose mother, Frenesi Gates, began life as the socially conscious daughter of an old left Wobbly family and during the Sixties became a radical filmmaker. Frenesi's life was turned around by the villain of the novel, Brock Vond, a federal prosecutor who forced Frenesi to become a sting operative for the Federal Bureau of Investigation. At the beginning of the novel, Frenesi's whereabouts are unknown, and her future is cloudy because the Reagan administration's budget cutbacks have caused her job to be eliminated.

Vond is trying to find Prairie so he can use her to influence his former lover, Frenesi...