By accident, the content of a computer encyclopedia is transferred into the brain of Dexter Riley, a less than average college boy. Because of his newly acquired knowledge he competes in a quiz show between various universities, where he sweeps all the points. A wiz kid from another university finds out about his cheated wisdom and does everything to discredit Dexter.

The Herlihys are a working class family from Chicago whose three children take wildly divergent paths: Brian joins the Marines right out of High School and goes to Vietnam, Michael becomes involved in the civil rights movement and after campaigning for Bobby Kennedy and Eugene McCarthy becomes involved in radical politics, and Katie gets pregnant, moves to San Francisco and joins a hippie commune. Meanwhile, the Taylors are an African-American family living in the deep South. When Willie Taylor, a minister and civil rights organizer, is shot to death, his son Emmet moves to the city and eventually joins the Black Panthers, serving as a bodyguard for Fred Hampton.

Silent since losing his hearing to meningitis, young Toby Wyler takes a bitter stance against the world and his family, refusing to accept his new stepfather. But when a highly trained orangutan named Casey is thrown from a truck near Toby's home, the boy soon has a secret friend he can communicate with via sign language.

Ernest, a lovable loser who works as a summer camp handyman and dreams of becoming a guidance counselor, must find a way to inspire a group of juvenile delinquents while stopping a shady strip mining company from closing the camp as well.

After a freak, fatal accident, the soul Karl—aka The Address Book Killer—ends up trapped in the electrical grid. He targets Terry and her son for his next victims, turning home technology against them as deadly weapons.

The inimitable VW Beetle is losing all his races and destined for the scrap heap until mechanic Hank takes him over and gives him a new lease of life. Soon, Herbie is winning again, to the fury of his previous owner, who builds a menacing black bug to challenge Herbie to the ultimate race.