After crashing in a stock-car race, Fonzie begins to worry about what will happen when his number comes up. Al suggests Fonzie seek the guidance of his brother, Father Anthony Delvecchio.
Ralph takes bets on football games at 10:1 odds. The Green Bay Packers pull out an unexpected win, and Ralph owes a lot of people a lot of money.
Fonzie gets a dog, and she escapes when Ralph and Potsie accidentally leave the gate open. Ralph tells Fonzie that the dog, Spunky, was stolen.
Howard comes up with the idea for a trash compactor, and Fonzie becomes his partner to help him build it. They become very excited about the success they could achieve and present "The Gulper" to a corporation for consideration.
Thinking her life is dull and that she's always treated like a little kid, Joanie wants to join the Red Devils' gang.
Richie, Fonzie, Potsie, and Ralph receive notices from the army to report for physicals.
After passing make-up health exams and getting permission for Fonzie to participate, the guys arrange for aspects of the graduation ceremony to be sped up in order to accomodate the inclusion of Fonzie's speech.
The guys discover that Fonzie has been going to night school so that he can graduate with them. Marion gave them this information, and she becomes worried that Fonzie will be angry with her for telling.
Not having enough to do now that Richie and Joanie are growing up and because she feels as though she's a slave to Howard, Marion gets a job waitressing at Arnold's.
Richie makes a lucky shot to win a basketball game and suddenly becomes a big hero.
To get some publicity, Al tries to have someone break a world record at Arnold's. Meanwhile, Fonzie's cousin, Angie, is in town for a visit and proves to be extremely clumsy.
Richie and the guys organize a time capsule for a school project. Howard agrees to let them use the vault at his store for the capsule, and Potsie accidentally locks them all inside.
Fonzie meets an older woman whose car he fixed and agrees to meet her the next day for doubles tennis at a country club.
Richie falls in love with a Wisconsin Cola poster girl and poses as a successful hardware businessman in order to meet her.
Kirk, the new acting sheriff, tries to exert his power by forcing Fonzie to leave town.
Richie, wanting to become a tough reporter, sets out to investigate the food at Jefferson High. During his investigation, he discovers that Fonzie is afraid of liver.
Joanie enlists Fonzie to be her partner for a marathon dance at Arnold's. She desperately wants to outlast cheerleading captain Jill Higgins who had cut Joanie from the squad earlier. Prior to the dance, however, Fonzie's motorcycle breaks down, and he is forced to push it for 12 miles.
To allow Richie to have a night alone with his girl, Fonzie allows him to use his apartment and claim it as his own. Fonzie needs some rest, so he sleeps in Richie's bed without Howard, Marion, and Joanie knowing.
Potsie saves Fonzie from a fire at the garage. Out of gratitude, Fonzie grants Potsie any one favor, and Potsie wants to pal around with the Fonz.
Fonzie's friend's pregnant wife stays with Richie at the Cunningham house while the rest of the family is away on vacation.
After having been in several fights recently, on the advice of the Cunninghams, Fonzie agrees to see a psychologist.
Though he's up against the two Mallachi brothers by himself, Fonzie is able to win the demolition derby. While waiting at the hospital for Pinky to be released, Fonzie tells Richie that he loves her and wants to marry her.
Fonzie assesses the damage to Pinky's car, and Richie asks Howard to delay the start of the demolition derby.
Fonzie reunites with an old flame, Pinky Tuscadero, who is in town to perform motorcycle stunts at a demolition derby.
