Young bachelors and inseparable best friends, Fred Flintstone and Barney Rubble, have just secured their positions as crane operators at Slate & Company. Eager to embark on a new chapter in their lives, the duo yearns for romance. Their wish catches the attention of a quirky little green alien known as The Great Gazoo, who has been exiled to Earth and can only be seen by the two friends. In the meantime, Wilma Slaghoople expresses her desire to lead a more ordinary life filled with everyday pleasures such as bowling. Unfortunately, her aspirations clash with her controlling mother, Pearl, who insists that Wilma should marry the affluent Chip Rockefeller, a casino owner. In a fit of frustration, Wilma runs away to seek refuge with a Bronto King in Bedrock.
At the local diner, waitress Betty O'Shale mistakenly assumes that Wilma is "caveless" and offers her a place to stay, as well as a job. Meanwhile, Fred and Barney have caught the attention of the waitresses and are soon invited to a carnival—where Fred pairs off with Betty while Barney accompanies Wilma. After a stroke of luck at a carnival game, Fred wins an odd prize: an egg that eventually hatches into a playful baby dinosaur he names "Dino." However, both men realize they might not be truly connected to their respective dates, leading to an eye-opening swap for the two.
As they navigate their new relationships, Wilma invites them to a celebration for her father, Colonel Slaghoople, where Fred plans to propose. However, the evening takes a turn when Chip critiques Fred's job, sowing seeds of doubt in Wilma's mind. While Colonel Slaghoople welcomes Fred and Barney into his home, Pearl is less than thrilled about the boys, creating tension. Their family dinner ends in chaos as Dino wreaks havoc, yet Wilma stands by Fred's side.
Chip, feeling threatened, feigns generosity by extending an invitation to his Rock Vegas resort, but Fred is unaware of the ruse designed to tear him from Wilma. Chip is in neck-deep with gangsters, making plans that hinge on marrying into the Slaghoople family fortune. The situation escalates when Fred, under pressure, plunges into gambling, hoping to earn enough to impress Wilma, only to be misled into further trouble.
In a series of misunderstandings, Betty racks up her own emotional turmoil as Barney is seen in a compromising position with Roxie, Chip's girlfriend. Miscommunications lead to Fred's ultimate downfall as Chip orchestrates evidence that frames him for robbery. Trapped behind bars, Fred and Barney meet The Great Gazoo, who unveils Chip's nefarious intentions. Rallying together, Fred and Barney make a daring escape from prison, complete with disguises to evade casino security.
As the drama unfolds, Barney confronts his feelings for Betty, leading to a reconciliatory moment that inspires them to warn Wilma of Chip’s true nature. The climax reaches a peak when Fred, disguised as the entertainer Mick Jagged, sings to Wilma and makes a heartfelt apology. In a stroke of clarity, Wilma recognizes her true affections for Fred, decisively rejecting Chip’s proposal and accepting Fred's instead.
Their love story culminates in a charming wedding at the Rock Vegas Chapel of Love, while external conflicts play out with Chip and the gangsters. As Fred and Wilma exchange vows, their friends and family join in jubilantly, singing “Meet the Flintstones” to celebrate the couple's new beginning. Amidst all the joy, Betty catches the bouquet thrown by Wilma, and the couples drive away happily with Dino and Gazoo, leaving behind happy memories and a heartfelt farewell from their loving friends.
