The Beverly Hillbillies series starts with the OK Oil Company learning of an inadvertent strike in Jed Clampett's Ozark swamp land. Patriarch Jed moves with his family into a mansion next door to his banker (Mr. Drysdale) in the wealthy Los Angeles County city of Beverly Hills, California, where he brings a moral, unsophisticated, and minimalistic lifestyle to the swanky, self-obsessed, and sometimes superficial community. The theme song introduces the viewer to the world's only fortunate hunting accident – whereby Jed shoots at game but instead hits "black gold".

Source: Wikipedia.org