Howard feels that Joanie has been seeing too much of Chachi lately, so he offers her her own phone if she agrees not to see Chachi for two weeks. Joanie and Chachi sneak off to a concert in Chicago and have to stay in the same room, the honeymoon suite, at a motel because it is the only one left.

Fonzie is given the job as teacher of auto mechanics at Jefferson High School. He gets frustrated when his students don't pick everything up as quickly as he did when he was a kid.

Roger Phillips, Marion's nephew, comes to Milwaukee to become an English teacher and the basketball coach at Jefferson High School. He gets off on the wrong foot with Fonzie after he inadvertently empties his locker, insults him, and crashes into his motorcycle.

Despite Howard's objection, Joanie decides to buy a car because she and Chachi are tired of having to double-date, and Chachi cannot afford to buy his own.

On Christmas Eve, a terrible blizzard traps Howard and Joanie at the hardware store and Fonzie, Potsie, Chachi, Jenny, and Roger at Arnold's.

Al announces that he's given up his search for Rosa Coletti, a woman with whom he was involved 20 years ago. However, he receives a letter from his mother saying that she's found Rosa and that she'll be coming to Arnold's next Saturday night.

Chachi tells Fonzie that his motorcycle has seen better days, but Fonzie refuses to junk it. He finally decides to get a new bike after crashing his old one but has to save his money a little longer. Joanie suggests to Chachi that they all pool their money with Fonzie's to surprise him with a new bike for his birthday.

Meanwhile, Arnold's has a new cook, but Fonzie's sixth sense tells him that something isn't right about him.

Fonzie comes down with a terrible toothache but refuses to see a dentist. Meanwhile, Howard is upset about Joanie's choice of attire for a wedding she's attending.

After a day of everyone asking favors of him, Fonzie has a nightmare about a mad scientist draining his cool.

Chachi becomes jealous after seeing a kissing scene involving Joanie and another actor during rehearsals for a school musical. Fonzie also considers quitting as director.

After Jenny's date dumps her before a big masquerade ball, Fonzie agrees to take her. They dress as a bride and groom and, as part of a talent portion of the party, have a make-believe wedding. However, since the captain of the boat performed the ceremony, the marriage may be legal. Roger believes they can get the marriage annulled if Jenny agrees to it, but, instead, she comes into Fonzie's apartment carrying suitcases.

Because she's never been to his house or met his mother, Joanie thinks that Chachi is ashamed of her. Fonzie invites the Cunninghams over to the Arcola's for dinner on Chachi's behalf. Fonzie surmizes that Chachi is embarrassed of his mother and uncle and of the fact that they're poor.

Potsie falls behind on his rent and is forced to move back in with his parents. However, after learning that Lori Beth's roommate likes men who live alone, Potsie has to stay in his apartment. He tells Fonzie that he can get quick cash but won't say how.

Chachi discovers a great basketball player who recently transferred to Jefferson High. However, he initially holds back when performing for Roger and, suddenly, changes his mind about being on the team when his father orders him home in the middle of a practice.

Desperate to get Chachi on the school's basketball team, a scout for Eastern Florida University offers him a scholarship and several other superfluous perks - including a cheerleading scholarship for Joanie. Fonzie is extrememly excited for Chachi, but Howard and Roger think the scholarships are too good to be true.

Marion hurts her back before a big bowling game, but Howard finds a new partner in the lovely Fern Flagg. He had told Marion that she was an old spinster woman. Marion and Fern meet each other, and Marion is furious at Howard for lying to her about Fern's appearance.

Meanwhile, Jenny receives a product in the mail called the Ajax Bust Builder.

Fonzie takes his auto shop class to an out-of-town junkyard and meets a waitress at a diner whom he thinks is his mother.

Chachi struggles with an essay on the causes, hardships, and influences of immigration until Fonzie tells him several stories in a series of musical vignettes.

Joanie prepares some home movies to send to Richie. She mentions that she and Chachi have had their problems over the summer. In the movies, Lori Beth announces that she's going to have a baby, Al's mother visits for the entire summer, Howard is consumed with Braves baseball, and Fonzie and his former gang, the Falcons, get ready to settle old scores with a rival gang.

Fonzie's Falcons and their rival gang, the War Mongers, attempt to settle their old scores with a game of softball. The outcome is disputed, so they end up rumbling. Marion confronts Howard about his anxiety over becomming a grandfather, and Chachi continues to try to make up with Joanie.

Chachi tells Joanie that he wants to date other girls and soon realizes that he's made a big mistake. He tries to straighten things out with her, but she goes out on a dinner date with another guy.

Lori Beth asks Fonzie to be her coach in a new birthing method called natural childbirth. He's fully on board until he learns he has to be in the delivery room with her.

Fonzie substitutes for Roger in his hygiene class, and, as a prank, the students hide the lesson plan and tell Fonzie they're learning about sex. Roger is later informed that he will be fired as a teacher as a result of Fonzie's teachings.

In order for Jenny to join the Rondells, a popular club, she has to steal a statue from Pfister Park and bring it to their clubhouse. Joanie is there to help, and they are both caught by Officer Kirk.

Joanie takes care of Richie Jr. for the weekend while Lori Beth visits Richie in Greenland, Howard and Marion go to New York on business, and Fonzie is away at a teacher's convention. Jenny invites several people over for a party against Joanie's wishes. On top of that, the boiler breaks down.

Dateless for an upcomming concert, Jenny is set up with Eugene Belvin by Joanie and Chachi. They, along with Fonzie, try to make Eugene appeal to Jenny by making him seem more manly.

Joanie has to decide where she wants to go to college: UCLA or the local UWM. She wants to go to UCLA, but Howard very much wants her to go to UWM, even offering her a new car as incentive. After much deliberation, Joanie announces that she's not going to college at all.

Fonzie and Chachi's grandmother becomes very upset at them for suggesting that she move into a retirement home after they observe some signs of senility.

Al is chosen to head the Leopard Lodge's annual Poobah Doo Dah when he says he can get his distant cousin, Frankie Avalon, to perform. However, as Al is auditioning other acts to round out the show, Avalon calls to say he can't make it.

Initially furious that the music teacher, Cynthia Brannigan, hires the Boston Conservatory Orchestra for the annual Jefferson High concert, Fonzie changes his tune when he realizes that famous composer Tchaikovsky was very much like himself. Fonzie decides to get the entire Jefferson High gang to like classical music.

The gang tries to get the Lone Ranger, Fonzie's idol, to appear at his birthday party. Meanwhile, Fonzie thinks about becomming a one-woman man.

Roger's family sends his brother, Flip, to Milwaukee with the hope that Roger can straighten him out. Roger entrusts Flip to pick up Marion after he attends a Fats Domino concert, but he skips the concert to hang out with some hoodlums and leaves Marion to walk home in the cold.

After a day of fishing with Howard, Chachi gets to thinking about his future when he realizes that being a success in the music business is a long shot. He leaves the house determined not to come back until he finds a career that would be sufficient to support Joanie should they get married one day. He tries his luck at being a salesman.

Jealous of Joanie's friendship with a new girl in school, Mikki, Jenny spreads a false rumor that Mikki is pregnant. As the rumor circulates, Fonzie is added to it as being the child's father.

After a month of dating, Al wants to ask Chachi's mom to marry him. Being an old fashioned guy, Al asks Chachi's permission. He grants it but doesn't think she'll want to marry Al.

After realizing they're dating people that look like each other, Joanie and Chachi decide to meet in order to explore the option of getting back together.

Meanwhile, Fonzie wants to adopt an orphaned boy to whom he's been a Big Brother.

Fonzie's adoption request is reconsidered after a stern talk by Howard to the adoptions administrator.

Meanwhile, Joanie and Chachi continue to prepare for their wedding.