After a three day health food convention in Cleveland, Stella and Dee arrive home to find Stella's Uncle Buster being arrested for causing an explosion on Harper Valley Drive with one of his latest screwball inventions. Annoying and intrusive at times, but after a heart to heart talk with her compassionate mom, daughter Dee learns to love Uncle Buster as much as Stella.
At Stella's 25th High School Reunion, Calvin Kendall, an old boy friend of Cassie's, makes a play for Stella, causing the only fight that the two best friends have ever had. When Stella learns that Calvin is married she threatens to tell Mrs. Kendall about his cheating ways unless he repairs the damage and hurt feelings that he has caused her best gal pal Cassie.
Flora Reilly tries to shut down a local mens club, unaware that Mayor Harper and her son-in-law Bobby are members. After Stella gets busted for an illegal lottery ticket and thrown in jail, she discovers from public records that Flora's great grandmother founded the club and entertained men in a burlesque revue.
Stella gets a new job as Mayor Harper's assistant and a bribe from a shady man called Slick. He offers her $10,000 to steal copies of the construction bids for the new wing of Harper Valley's Hospital.
After the Scrooge like CEO of Reilly Enterprises (Flora Reilly) refuses to sign the Holiday bonus checks for all her employees, she is knocked unconscious by a falling Christmas tree. Later, she is visited by three ghosts who show how her miserable life will end if she does not change her evil ways.
A destructive motorcycle gang called The Banditoes has arrived in Harper Valley. The gang's leader, Clutch Breath has informed town matriarch Flora Reilly that they have no intention of leaving unless Stella Johnson goes with them!
Flora Simpson Reilly writes a play for a community theatre production and casts her daughter in the lead role of the Viking Princess. But, after Wanda falls and injures herself during a rehearsal, the director insists that Stella takes over the starring role in Flora's dramatic epic, "The Curse of the Widow's Heart".
When the town's fire department, run by Flora Reilly fails to respond to a local neighborhood blaze because of irresponsible volunteers and antiquated equipment, Stella demands that the town council elect a new fire chief. But, when Stella is elected to the position, Flora and her daughter Wanda do everything in their power to sabotage her efforts to improve the departments efficiency.
The townspeople of Harper Valley think that Stella has flipped her wig when she becomes nasty and aggressively pursues a married man (Bobby Taylor) in a public restaurant. Stella has a hard time convincing everyone that her look-a-like cousin Della is actually the brazen hussy !
With the help of a charismatic union organizer named Kowalski (Sal Viscuso), Stella joins the picket lines to protest the unfair working conditions in Harper Valley which is run by the ruthless Flora Simpson Reilly.
Flora's rich cowboy nephew from Texas has agreed to give her millions of dollars to make improvements at the Reilly Paper Mill, with one condition. Cousin Claude is depressed about his love life and wants Aunt Flora to hook him up with that pretty little heifer, Stella Johnson !
Stella chaperone's Dee and her friends on a school related camping trip deep in the woods of Grizzly Gap. During a friendly poker game, Stella's Uncle Buster and Mayor Harper learn that a dangerous criminal has escaped from jail and is heading back to his old hide-out at Grizzly Gap.
A handsome newspaper publisher named Tom Meecham gets on Flora's bad side when he prints an editorial in the local paper criticizing one of her companies. To make matters worse, he invites Flora's enemy, Stella Johnson (as his date) to a lavish dinner party thrown by the grand dame herself, where a political debate ensues.