Grandpa reluctantly agrees to let Luke and Kate trade the McCoys' family car (plus $80) for a newer model, but they regret their decision when they realize that he was genuinely attached to the ancient vehicle.
Little Luke desperately wants to join the school band as a trumpet player, but he has no talent for the instrument and Grandpa feels compelled to resort to chicanery in order to help him prevail when tryout day arrives.
Kate insists that Luke take dancing lessons in order to improve his social graces, but she is unpleasantly surprised to learn that his teacher is an attractive young woman.
When it seems that Grandpa's location of water by divining rod is a failure, Luke employs a geologist and drilling equipment as Amos gloats at the apparent unsuccessful outcome of Luke's chosen methods.
Grandpa solicits George MacMichael's help in turning the tables on two swindlers who convinced him to pay $35 for a worthless dog, but he begins to have a change of heart when he discovers that Little Luke has become quite attached to the animal.
Luke's reluctance to kiss Kate in public causes her to feel unappreciated, especially when she notes how demonstrably affectionate their friends George and Betty Emery act toward one another.
The stakes escalate as Flora, Kate, and Hassie refuse to go to the annual Grange Dance with Grandpa, Luke, and Tommy unless they receive a proper apology for Grandpa's remarks to Tommy about how a man should "handle" women.
Grandpa and Kate are dubious when Luke gets a part-time job as a shoe salesman, but when he loses the job the rest of the McCoys unknowingly come to his aid by going to the store en masse to buy shoes.
When the McCoy's learn that hometown girl Glory is a Hollywood celebrity, Luke fears Kate will be dissatisfied with her life when the McCoy's visit her so when Glory comes to visit, the McCoy men try to paint Kate's life rosier than it is.
The McCoys dig up a brontosaurus leg bone on their property. Kate wants to donate the bone to a museum, but Grampa would rather cash in on a roadside stand tourist attraction.
When novice driver Kate mistakenly believes that she has damaged the family car, her heartfelt efforts to make amends cause the real culprit (Grandpa) to become increasingly conscience-stricken.
After Grandpa tells Little Luke and his friends an exciting (but untrue) story about serving with Teddy Roosevelt in the Spanish-American War, he is invited to appear as a guest of honor at a public Veteran's Day celebration.
An aging and nomadic Arapaho Indian Chief insists that he can repay the McCoys' kindnesses by doing an extended sequence of dances that will bring much-needed rain.
Determined to fit into a tight "Anniversary Dress" and concerned that she is taking after her corpulent Aunt Bessie, Kate embarks upon a crash program of diet and exercise.
Grandpa's determination to keep Hassie's 15th birthday party a surprise causes her to become genuinely hurt and angry when she becomes convinced that no one cares about the occasion.
A conflict arises between Luke and Kate when Grandpa monopolizes all of Luke's free time, but Grandpa decides to make amends after Pepino makes him aware that he is the source of the problem.
Grandpa and Luke convince Kate to enter a local merchant's "Mrs. Homemaker Contest" when they realize that the first prize of $50 in merchandise would almost exactly cover the cost of the new gun they've been admiring.
Grandpa's attempts to hide his furniture from the tax assessor lead the McCoys' minister to conclude that the family is experiencing serious financial difficulties
When Grandpa injures his arm, he sorely regrets that he stubbornly (and secretly) refused to join the rest of the family in taking out a group health insurance policy offered by the Grange.
When Grandpa and George MacMichael realize that their house painting contracts with the "Sparkle Paint Company" are a fraud, they utilize a ruse to try to recover their money.
Envious Grandpa attempts to sabotage a camping trip arranged by Hank Johnson, a generous neighbor who has become increasingly popular with Little Luke and his friends.
Grandpa volunteers for a lodge job to shame Luke for refusing it and then finds the task is to assist in answering lodge letters but because he is too vain to announce his illiteracy, creates chaos faking the assignment.
Fastidious actor Sterling Ames injures his back on the McCoys' property and must remain on their sofa for several days, much to the annoyance of "cantankerous" Grandpa.
Grandpa decides to turn the tables after a fast-talking shooting gallery proprietor hustles Little Luke out of $14 in proceeds from the sale of church social tickets.