Fonzie becomes weary about his inability to become happy by plowing through dates. He finds love at first sight with a woman he sees on an escalator, although he doesn't catch her name, and orders everyone at Arnold's to find her. Potsie recognizes the woman from his dad's gas station as Ashley Pfister, so Fonzie visits her at her apartment in hopes she will fall in love with him. Ashley proves to be unlike any other woman whom Fonzie ever dated, as she does not immediately fall under his influence.

Joanie wants to move to Chicago with Chachi and attend Northwestern University.

Notes: Erin Moran and Scott Baio appear in this episode to set up the spinoff Joanie Loves Chachi. Also, although out of order, this was the first episode of the season produced.

Howard and Marion try to keep busy in their newly-empty house, while Fonzie decides to sell his half of Arnold's.

Note: This episode marked the return of Pat Morita as Arnold, the original proprietor of Arnold's Drive-In; There have been 151 episodes aired since Arnold last owned "Arnold's"

Guest starring: Harriet Nelson and Jane Wyatt.

Fonzie takes Heather to the circus, as Howard's niece K.C. moves in.

Note: Crystal Bernard returns in her new role of Howard's niece, K.C. Cunningham.

An old nemesis of Fonzie (special guest star Tom Hanks) returns to seek revenge on Fonzie at an inopportune time.

Joanie and Chachi have a chance to appear on TV playing folk music; however, Fonzie is upset that folk is usurping rock 'n' roll's place in people's hearts and minds.

Guest starring: Scott Baio as Chachi Arcola; Erin Moran as Joanie Cunningham.

Ready to settle down after all these years, Fonzie declares his love for Ashley by asking her to go steady; but when an old girlfriend of Fonzie's (Melinda Naud in her role of Paula Petralunga from Season 3) shows up needing help, it causes problems between Fonzie and Ashley. In a subplot, Howard gives K.C. driving lessons.

Recurring guest: Scott Baio as Chachi Arcola.

Note: Melinda Naud returns in her role of Paula Petralunga, who had appeared in a few episodes in Season 3 as Fonzie's most spectacular conquest.

Melvin Belvin takes K.C. to Arnold's costume ball.

Business is down at Cunningham Hardware, leading Howard to consider some very difficult options--one of which includes closing the store permanently.

Recurring guest: Erin Moran as Joanie Cunningham.

When Heather asks Santa to patch up the rift between her mother and grandparents, Fonzie decides to make her wish come true. In a subplot, Howard's brother Dick is visiting.

Roger's old flame ( Wendy Schaal) fans the fire when she returns to town.

Ashley introduces Fonzie to her estranged family.

Flip goes out with some friends who drink and become intoxicated; and while under the influence, the driver hits Heather with his car, severely injuring her. A furious Fonzie severely disciplines Flip when he finds out Flip was involved in the hit-and-run accident as well.

Note: Final appearance of Scott Berenstein as Melvin Belvin.

K.C. dates a convict who is on work release at Fonzie's garage.

Fonzie gets a record producer interested in Joanie and Chachi's music, but he's less excited about their band.

Special guest stars: Scott Baio as Chachi Arcola and Erin Moran as Joanie Cunningham, as well as members of the cast of Joanie Loves Chachi; including Derrel Maury, Winifred Freedman and Robert Pierce.

Side note: The logo of the fictitious "Holstein Records" seen in the episode is a knockoff of RCA Victor's famous Nipper the dog logo, which featured a Holstein cow staring into a gramophone.

Fonzie and Ashley celebrate their six months together at the Cunninghams', looking back on their relationship through "flashback scenes" (most of which were not actually part of "A Woman Not Under the Influence").

Note: Although out of order, this was the last episode of the season produced.

Fonzie, Potsie, and Roger report for Army Reserve duty. Fonzie promises Heather that he'll be at her birthday party--until he learns that Officer Kirk is their commanding officer.

Note: Final appearance of Ed Peck in his role of Officer Kirk.

Fonzie becomes the center of attention at the wedding of a friend ( Peter Scolari).

Note: Al Molinaro returns as Father Anthony Delvecchio.

Fonzie babysits Heather on the night of a big fight on TV that Fonzie and the guys plan to watch, which conflicts with Fonzie's attention to Heather. Meanwhile, Joanie and Chachi return to Milwaukee--to stay.

Note: This episode marks the return of Erin Moran and Scott Baio in their respective roles of Joanie and Chachi to the series' regular cast, due to the impending cancellation of Joanie Loves Chachi.

Joanie decides to move back in with her parents.

Notes: Al Molinaro and Ellen Travolta return in their respective roles of Al Delvecchio and Louisa Delvecchio. Also, this episode marks the final appearances of Linda Purl and Heather O'Rourke in their respective roles of Ashley and Heather Pfister.

Jenny sets her sights on dating an Olympic swimmer. Meanwhile, Fonzie wants a pool.

Note: Final appearances of Crystal Bernard as K.C. Cunningham, Billy Warlock as Flip Phillips, and Cathy Silvers as Jenny Piccalo. Silvers would return as a guest in her role of Jenny Piccalo in the series finale "Passages."