Luke and Louise feel they have a real problem with Greg, who is addicted to telling fantastic stories about imaginable playmates and people. When they return home from a day's outing, after leaving Greg with Pepino, he tells them three escaped convicts had been captured by the police at their home, and they decide it is just another one of his tall tales.
Grandpa bristles at Sir Fergus, head of the Scottish branch of the McCoy family, when he arrives and proceeds to exercise all the authority of the Laird of the Clan. Grandpa's anger erupts when Sir Fergus extends his influence to Grandpa's pet goose, Floyd. Grandpa begins one of his devious plots to oust the Scotch usurper from his position of power.
Luke is horrified when Uncle Rightly promotes a corn growing contest at the Grange and is so carried away he volunteers a $500 award to the winner in Grandpa and Luke's name. When Luke learns Uncle Rightly doesn't have the $500, it becomes a major problem of raising the money and saving face with the Grange members, but Rightly solves the problem in an unusual way and comes up with the prize money.
Luke lands the enjoyable job of teaching calisthenics at a ladies' health club. Grandpa decides that Luke's presence there may attract some business for the McCoy roadside fruit stand. Grandpa then surreptitiously tempts the dieting health club enrollees with a variety of tasty fruit products, thus undermining the efforts of unsuspecting Luke.
Grandpa thinks he has discovered a gold mine in the sky when an Army paratrooper lands with destructive force on a dilapidated chicken coop that was already marked for the scrap heap. When an Army captain arrives to assess the damages, Grandpa paints a black picture. Luke, however, takes a dim view of Grandpa's shenanigans and bluntly tells him so.
Grandpa becomes romantically entangled with three matrimonially inclined widows when he encourages their interest just enough to promote some free housecleaning chores and a few well-laundered shirts. Luke and Pepino take a dim view of his scheme when it becomes apparent that the three marriage-minded women are literally doing all the McCoy housework in separate shifts.
Grandpa becomes involved with diplomatic relations and the U.S. State Department when a foreign nation's farm tour visits neighbor George's ranch and Grandpa pursuades the group to detour by the McCoy farm. At first it appears Grandpa has committed a colossal faux pas, but his apparent blundering develops unexpected consequences.
Grandpa arranges for Tilda Hicks from Smokey Corners to join the McCoy family as housekeeper, and she immediately sets her cap for widower Luke McCoy. The arrangement proves highly successful until Tilda attends the neighborhood dance with Luke and scores an immediate hit with the local masculine populace.