After his single makes it onto the record charts, Chachi is invited to go on tour with the Beach Boys as one of their opening acts. However, he quits the tour after learning he has diabetes.
Joanie brings home one of her students in an attempt to help her with her drug problem. The student promises Joanie that she'll make changes in her life, but she immediately takes several pills after everyone has gone to bed.
After having to borrow money from Marion and being hassled by Fonzie about being a bum, Chachi takes a job as a dance instructor. Meanwhile, Howard takes away Potsie's salary after he sells power drills for $13.05 less than cost.
Marion and Joanie take a trip to Mother Kelp's to help her move. From the time they arrive, Mother Kelp does nothing but critcize Marion. Meanwhile, Howard, Fonzie, Chachi, and Roger spend the weekend playing poker.
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.
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.
Howard is offered the vice-presidential position at a large hardware-store chain and considers taking it and moving to New York. Despite nothing being final and Fonzie feeling as though the Cunninghams are pushing him to leave, he decides to immediately move out of his apartment.
Fonzie meets a beautiful woman, Nancy Haley, at his garage while listening to the radio in a beat-up 1955 Chevy. He takes the woman home, but when he goes back to return her purse, an older woman tells him that the Haleys moved out ten years ago when their daughter was killed in an automobile accident.
Chachi is hesitant about asking girls out for fear that he will be rejected. Fonzie tells Chachi that girls will ask him out because he has the Fonzarelli power.
Howard is jealous and upset when Marion's high-school boyfriend, Frederick, comes to visit. He becomes enraged when Frederick takes Joanie out on a date.
Fonzie is accused of hitting a trouble-making student but refuses to testify at a school-board hearing. By not doing so, he runs the risk of being ruled against and getting fired.
Joanie accepts an assistant teaching position at Patton High and immediately encounters trouble when a student has a crush on her.
Fonzie's long-lost brother from San Francisco, whom Fonzie didn't know existed, tracks Fonzie down in Milwaukee. Fonzie is, initially, happy to have a brother but soon comes to hate him.
Roger is the new principal of the tough George S. Patton Vocational High School. He thinks he can handle the students there but is sorely mistaken.
After being nothing more than a coatrack for Fonzie's scarf during a rumble, Chachi enters the city boxing championship tournament to earn his respect. Fonzie is elated when Chachi wins his first fight.
Still upset about having given up on his dream as a screenwriter and having to pretend to be happy all of the time, Richie takes out his frustrations on everyone around him - including punching Fonzie in a bar.
Richie (with Lori Beth and Richie Jr.) and Ralph return from the army. Howard is able to get Richie an interview with The Milwaukee Journal, but Richie doesn't appear to be interested.
New events in Joanie's life cause Chachi to resent her for not having enough time for him. Each has their own solution: Joanie wants to break up, and Chachi wants to get married.