Fred and Barney become enmeshed in international spyjinks when they inadvertently become involved with a beautiful foreign agent and the villainous Dr. Sinister, who is intent on world domination.

Fred stands to inherit his Uncle J. Giggles Flintstone's estate under one condition: The family has to spend a night in his relative's eerie mansion staffed by creepy old servants.

Samantha and Darrin Stephens guest star from television's ""Bewitched"" (voiced by series star Elizabeth Montgomery and Dick York). Darrin goes boating, while Samantha joins the Flintstones and the Rubbles for a camping trip, which ends up pitting the men against the women. Aided by Samantha's witchcraft, the women manage to out-do the men at every turn.

After Fred takes a job as a department-store Santa, he proves so successful that the real Santa asks Fred to stand in for him and deliver presents on Christmas Eve.

To commemorate his tenth wedding anniversary (which he only remembers because it falls on ""Trash Day""), Fred wants to buy Wilma a Stoneway piano. He finds a hot deal--ultimately too hot--from a shady, cash-only businessman named 88 Fingers Louie.

When his neighbors' domestic fights suddenly end with the disappearance of the wife, Fred suspects Alvin Brickrock of foul play. After reading a detective magazine, he becomes convinced that Brickrock is really Albert Bonehart, wife-murderer.

Ailing Dino is taken to the vet, who diagnoses him as having a ""dinopeptic germ,"" which is common to dinosaurs but lethal in humans. But when Dino's x-rays are mistaken as Fred's, Wilma is alerted and told to prepare the only known cure: keeping the patient awake for seventy-two hours, without telling him why.

Wilma is still pregnant and Fred is trying to be calm. This shatters when the docter tells him the blessed event could happen any day now.

Fred and Barney learn that local talent is being sought for the Bedrock Bowl's premiere event, a television special starring Ann-Margrock (voiced by Ann-Margret). The boys go home and prepare for an audition, and are aided by Ann-Margrock herself (whom they fail to recognize), who comes in to the Flintstones' home to use the phone after her car breaks down.

Fed up with their jobs, Fred and Barney secretly plan to buy a restaurant, but then Fred has to deal with a suspicious Wilma who wants to know why two young girls (carhops who are seeking a job) are calling for him, and what the messages regarding two tons of dino-burger meat mean.

With a burglar on the loose in Bedrock, Betty decides to take judo lessons to protect herself. When Wilma wants to take lesson also, Fred ridicules the idea, arguing that one glimpse of a burglar would send her running in fear. To prove his point, Fred poses as the burglar and sneaks into the Rubble household, on the same night the real criminal shows up.

While plumbers at the Rubble home try to unfix Fred's attempted repair job, Betty and Barney move in temporarily with the Flintstones. The wives are convinced the forced togetherness will cause problems between Fred and Barney and they are right, although the husbands go to extreme measures to try to hide their bickering.

Hearing about a talent search for a new animal star to appear in ""The Adventures of Sassie,"" Fred coaches Dino and prepares for an audition. But Dino gets more than he bargained for when he lands the part.

In an attempt to cure Barney's hiccups, Fred offers his friend a swig from an experimental soft drink he has formulated. The brew turns Barney invisible, and Fred's elaborate attempts to hide the fact make Wilma wonder about her husband's sanity.

A series of strange accidents coupled with Wilma's sudden insistence on having Fred take out a life insurance policy, and her devotion to a murder mystery novel about a wife who bumps off her husband, causes Fred to wonder if his life is in danger.

Fred and Barney discover a visitor from another planet, the two-foot high, green Gazoo, who becomes their servant. An evening out at an expensive restaurant, supposedly with Gazoo treating, becomes a nightmare as the alien disappears, leaving the Flintstones and the Rubbles to wash dishes to pay for the food.

Fred and Barney jointly build a swimming pool, but Barney hogs the pool time, angering Fred. To get even, Fred hires a pal to pose as a police officer and break up one of his neighbor's pool parties.

Barney decides to surprise Betty with a belated engagement ring, which he gives to Fred for safekeeping. But Wilma discovers the ring and assumes it is a gift for her. Not wanting to shatter her illusions, Fred decides to buy a second ring, but doesn't have the cash. He cons Barney into going several rounds with a boxing champ in order to win a $500 prize.

Fred agrees to appear in a before-and-after weight reduction commercial, but is humiliated to learn that he is the before example. An offer of $1,000 if he can drop twenty-five pounds in a month fails miserably, as does every other diet plan, until an overeaters group takes him on as a challenge.

After telling Wilma that he is going to visit a sick friend, Fred runs off to a poker game, where he wins $200. To explain the money, he tells Wilma that he found the cash, and is dismayed when she places an ad in the newspaper to locate the owner.

Fed up with Fred's practical jokes, Barney decides to give him a taste of his own medicine. Barney sets up the gag with a stack of five, crisp $100 bills, his prize from the Sudsy-Wudsy jingle contest.

After a squabble about finances, Wilma seeks employment of her own. She applies for an office job at the Bedrock Radio & Television Corporation, but instead becomes the hostess of the ""Happy Housewife Show,"" a situation that makes things less than happy back at the cave.

With fatherhood impending, Fred promises to become more kind, considerate, and thoughtful. His willingness to change is strechted practically beyond endurance when his mother-in-law shows up to help Wilma during her pregnancy.

Trying to be neighborly, Fred and Barney offer to babysit for the Gruesome family, who've moved into Tombstone Manor next door with their weird kid and a menagerie of creepy critters.

On a visit to the Bedrock World's Fair, the Flintstones and the Rubbles take a ride in a time machine that sends them into the future with stops at ancient Rome and Arthurian England, and encounters with Christopher Columbus and Ben Franklin.