Jed Clampett is told by a representative of an oil company that the swamp behind his shack is full of oil. (The oil company employee has been hauled in by Jed's daughter Elly May who asks whether she can keep him.) Later, Mr. Brewster, the head of the oil company, does a deal with Jed. Jed tells Cousin Pearl that he'll receive 25 to 100 of "some new kind of dollar." Pearl, thinking Jed has been "slickered", asks what kind of dollar he's talking about. "Million dollars," Granny, Jed's mother-in-law, replies. "Jed, you're a millionaire," Pearl says. "Yeah, that's what ...
The Clampetts begin to settle in their new home in Beverly Hills, California. They are having to adjust to things such as refrigerators (Granny remarks how a ham will require two days to thaw out), ovens and the "cement pond." Jed also is having to confront how his daughter Elly May is maturing. He tells her that he, in effect, raised her as a boy and should not have. Jethro also encounters a flamingo that he thinks is a chicken (which causes Jed to suspect Jethro has been sneaking drinks of moonshine). Meanwhile, Miss Hathaway, executive secretary to banker Milburn ...
While Grannie boils pool water for washing (due to the "lack of a pump") and Ellie May gets a feminine make-over by Miss Hathaway, cousin Pearl is back at the cabin making eyes with the visiting oil man while he gives her a ride to the nearest phone.
Mr. Drysdale panics when Mrs. Drysdale comes back from Boston early, because she'll meet the Clampetts. He sets Miss Hathaway on a plan to get them to go to Palm Springs. Meanwhile, Grannie and Jed come to think Mrs. Drysdale is a drunk and make plans to cure her.
Grannie prepares her special mash to help cure Mrs. Drysdale of her drinking problem while Jed does as Mr. Drysdale suggests and buys stock: cows, goats, pigs, and chickens! Meanwhile, Mrs. Drysdale recovers from the shock of her first meeting with the Clampetts and is convinced she's imagining things.
Grannie wants to go home because folks is so unfriendly no one has come to call. Jed convinces her they should call on them, and they find that people welcome them and give them all manner of gifts when they show up on Halloween in their normal hillbilly clothes. Also, Jed works on getting Pearl to come visit while she's trying to get hitched to the oilman and find a young man for Jethrine.
Ellie May starts wearing dresses but takes it as an insult when someone says she looks like a city girl. Mr. Drysdale talks Jed into taking in his butler and upstairs girl in a plan to civilize the Clampetts, but they don't quite understand the idea of servants. Miss Hathaway takes Jethro bowling and begins to show an interest in him.
Jed enrolls Jethro at an exclusive Beverly Hills elementary school. Millicent Schuyler-Potts, the proprietor of the school, is aghast when Jed and Jethro show up, convinced this is part of some ghastly hoax. After Jed says that banker Milburn Drysdale is his neighbor, she calls the banker. It turns out that Drysdale's bank holds the mortgage on the school. Schulyer-Potts suddenly warms to the charms of the Clampetts, even if it means accepting Jethro as a fifth grader.
When Sonny Drysdale promises to give Elly May a ring, Granny thinks he's going to propose and becomes a matchmaker. Cousin Pearl can't stand the idea that Elly May will get married before Jethrine, so she sets to matchmaking Jethrine with Jasper Depew.