In the rockin' prequel to the live-action hit The Flintstones, we discover how Fred (Mark Addy) and Barney (Stephen Baldwin) came to meet their beloved wives Wilma (Kristen Johnson) and Betty (Jane Krakowski). As observed by a little green visitor from outer space (Alan Cumming), the path of true love is strewn with boulders - particularly in the shape of Wilma's scheming mother (Joan Collins) who's determined to reduce the romance to rubble.
The story begins with best friends Fred (Mark Addy) and Barney (Stephen Baldwin) graduating as Bronco crane operators from the Bedrock quarry. That same evening, they bump into a floating green alien (Alan Cumming), who has been sent to prehistoric Earth to observe the human mating rituals.
Betty (Jane Krakowski, from Ally McBeal) is a bubbly waitress who works at a Bedrock burger joint. Wilma Slaghoople (Kristen Johnston) yearns to mingle with the Bedrock community, escape the interfering clutches of her mother Pearl (Joan Collins) and find a man who will appreciate her for who she is... unlike Chip Rockefeller (Thomas Gibson).
Wilma runs away and befriends Betty, who mistakes her for a 'caveless' person and takes Wilma under her wing. The four meet and find romance at the Bedrock carnival.
When Wilma's mother finds out about Fred, she is determined to do everything she can to break them up - and Chip will do all he can to help.
Desperate to marry Wilma for her fortune, the scheming Chip offers Wilma and Fred, and Betty and Barney, an all-expenses-paid trip to his Rock Vegas casino hotel, planning all the while to get Wilma back into his clutches.