Fonzie promises the good Father Delvecchio (Al's twin brother) that he'll go one day without fighting. This, when a former rival, Rico, shows up in town with his merchant seamen crew and a mystery woman named Kat Mandu.
After Howard loses his temper and blasts her for forgetting to set the emergency brake and wrecking the car, Marion Cunningham opts for jail-time instead of a traffic fine to prove to her husband that she can be responsible for her actions.
Embarrassed when girlfriend Lori Beth makes him wear a silly Humpty Dumpty costume for the Homecoming Parade, unhappy Richie Cunningham storms off to a bar for a root beer and is swept off his feet by a sophisticated freelance photographer he meets there, beautiful Barbara Thomas.
Richie's reluctant friends agree with his plan to go camping in the woods over spring break under two conditions: that Richie, not Fonzie, will be the leader of the expedition ... and if nobody has a good time, it will be all Richie's fault!
After Joanie's boyfriend gives her a ring, big brother Richie worries that they will take their relationship to the point of no return at the Alamo, the special make-out spot at Inspiration Point that couples always remember...or try to forget!
Chachi is entrusted to close Arnold's, but he forgets to turn off the grill and carelessly tosses his apron on the hot surface. The result is a fire that destroys the drive-in restaurant, traps Fonzie, Ralph and Potsie, and lands Al in trouble with his insurance agent.
Fonzie agrees to help Al fund the rebuilding of Arnold's, but their business partnership - and the restaurant's future - is threatened when the two can't resolve disagreements on crucial aspects of the project.
When Richie's amateur commercial doesn't bring more customers into his Dad's hardware store, the Cunninghams hire a smooth-talking advertising expert who promises a huge increase in business but who also has a hidden agenda that challenges Howard's business ethics.
A dispute over the Cunninghams' electric bill results in Richie and Fonzie learning sign language after the Fonz falls hard for a pretty, hearing-impaired electric company receptionist who appears to be unaffected by his usually devastating charisma.
Potsie (aka Warren Weber) lands an audition to possibly become a performer at a local club. Making his egotism a bit difficult for his friends to deal with but,an underlying truth may alter Potsie's outlook.
Visiting Uncle Joe Cunningham puts Richie's journalism report on the right track by relating the (mostly) true, 1920's bootleg-battling exploits of his intrepid cousin, Assistant D. A. Cecil Cunningham.