Luke and Kate have a spat when Luke and Grampa show their disgust for public kissing by the Emerys, who have been married over five years. It takes Grampa to clear up the situation by explaining that there's a time and place for kissing, and that a public display of affection doesn't necessarily denote love.
Grampa is upset when he finds Hassie learning to dance to rock and roll music and using makeup in order to attract the attention of Tommy, the most popular boy in her class. When Kate convinces Grampa his ideas are old-fashioned, he and Luke decide to assist Hassie in her conquest.
When Kate is unsuccessful in trying to teach Luke to dance, she finally talks him into taking dancing lessons, much to Grampa's disgust. When Kate discovers the dancing teacher is a very attractive young lady, she becomes jealous.
Luke and Kate decide the McCoys should have a new car and trade in their old Ford. When Grampa learns of the transaction, he's heartbroken at losing a ""member of the family"" and tries to get it back. Flora MacMichael, knowing how Grampa feels about the old car, has bought it from the junk man and returns it to Grampa.
Grampa becomes involved with a couple of con men over a dog. He realizes they are trying to cheat him, and with the help of George MacMichael, they turn the tables on the crooks. Meanwhile, the entire McCoy family has become so attached to the dog, Mac, he becomes a member of the family.
Grampa's sales pitch persuades Luke to coach the little leaguers. Grampa: Walter Brennan. Luke: Richard Crenna. Kate: Kathleen Nolan. McGinnis: Willard Waterman.
Trouble begins when Luke unearths a valuable prehistoric bone. Luke: Richard Crenna. Grampa: Walter Brennan. Kate: Kathleen Nolan. Dr. Kirkwood: Eleanor Audley.
Grampa is aiming for the prize Kate may win in a homemaker contest. Amanda: Marjorie Bennett. Grampa: Walter Brennan. Kate: Kathleen Nolan. Luke: Richard Crenna.
Grampa puts on a convincing poor act for the tax man---and the neighbors. Wells: Richard Deacon. The Rev. Mr. Bascom: Thomas B. Henry. Grampa: Walter Brennan.
Grampa's scheme to withhold an insurance payment backfires. Grampa: Walter Brennan. Simmons: Rusty Lane. Sloane: Stanley Farrar. Luke: Richard Crenna.
A paint salesman gives the McCoys the brush---after swindling them. Grampa: Walter Brennan. Kate: Kathleen Nolan.
Grampa plans to knock Little Luke's new hero off his pedestal. Grampa: Walter Brennan. Little Luke: Michael Winkelman. Johnson: Lloyd Corrigan. Eddie: Raymond Karr.
Grampa gets a job answering mail. His problem: he can't read. Woodruff: Jack Mather. Grampa: Walter Brennan. Luke: Richard Crenna. Kate: Kathleen Nolan.