Refusing to go quietly into forced retirement from the police force, Howard's visiting dad, former Detective Captain Sean Cunningham, causes upheaval in the household while struggling to define the next phase of his life.
Jealous Richie Cunningham bridles at Lori Beth's too-enthusiastic participation in a charity kissing booth, while unable-to-swim Potsie Weber fears that the traditional dunk in the lake following his fraternity pinning ceremony will embarrass him in front of his intended sorority pin-ee, lovely Jennifer Jerome.
Sophomore Joanie Cunningham gets basic back-seat defense tips from Richie and Fonzie before her first "car date" with a senior boy, and then cramps her older brother's style when she and her date show up at his college "make-out" party.
When she hears that one of hubby Howard's friends divorced his middle-aged wife and married a much younger woman, Marion Cunningham fears that if she can't spice up her marriage, her fate may be the same.
What begins as a humorous escapade with a motorcycle turns into a tragic vigil for the Cunninghams and their friends. Richie purchases a motorcycle from Fonzie, but Howard angrily refuses to let him keep it, leading to a deliberately petulant tantrum from Richie to embarrass his father. But Fonzie convinces Howard that the bike is safe and Richie wears proper safety gear, so Howard reluctantly relents. Richie takes Lori Beth along one day while Fonzie is out and Chachi is repairing a truck rented by Al Potsie, and Ralph. The group is ecstatic when Chachi gets the ...
Fonzie and friends try to dig up what's depressing his faithful canine companion, Spunky, while Howard saddles Marion with a hundred pounds of potatoes to peel for his Leopard Lodge picnic's potato salad.
No one believes Richie's claims that he not only saw a flying saucer but personally interviewed its pilot, an alien named Mork, who tried to take him back to planet Ork as an example of an average, humdrum human.
Richie's girlfriend, Lori Beth, finds that the Cunninghams and their friends re-define the word "typical" when she interviews them for her college term-paper on what it means to be typical, middle-class Americans.
Fonzie's latest romantic interest,a ballet teacher,is secretly yearning to turn professional and dance with the greats in New York. Fonzie,however,has trouble accepting that she may forgo their relationship to pursue her dreams of fame.
Richie interrupts his summer job search to help choose a cute little meter maid from Fonzie's big black book to accompany dateless Al DelVecchio to the Sons of Italy banquet honoring him as Man of the Year.
Richie and Lori Beth fight over her casual friendships with other guys on the eve of a much anticipated trip with his band to play back up for girl-group, Leather and the Suedes, at remote Blue Ox Inn.
The Cunninghams and their friends go west to help run Marion's injured Uncle Ben's Colorado dude ranch, soon finding that they only have five days to pay the balance on a loan owed to nasty neighbor, H.R. Buchanan, to save it from foreclosure.
Pretty wrangler, Thunder McCoy, helps the Milwaukee city slickers stage the dude ranch's annual rodeo, planning to use the proceeds from the event to pay off the loan, while H.R. Buchanan lurks on the sidelines, hoping they'll fail.
Fonzie's new best friend is six-year-old Bobby, son of his girlfriend Peggy, whose husband abandoned them years earlier. Wrestling demons from his own past, Fonz faces an ethical dilemma when the father returns.
Committee co-chairmen Howard Cunningham and Al DelVecchio must somehow replace accidentally drunk magician, the Amazing Randi, star of the Leopard Lodge's annual Sunnyside Orphanage fund-raising dinner show.
Trying to save his reputation and his candidacy, Richie and his pals plan to steal the film that will soon be used to incriminate him after his sophomore class president opponent photographs him in a massage parlor.
A cold, snowy Wisconson Christmas finds Howard Cunningham trying to convince his family to put up a new-fangled, artificial tree, and a mysterious sailor delivers a gift from Fonzie's father, forcing the Fonz to deal with his long-suppressed feelings of abandonment.