Grandpa mixes up a love potion designed to make the opposite sex fall madly for anyone who drinks it.

Herman is suffering from insomnia. The only thing that will make him sleep is a late-night walk in the park. A 'monster' type creature has been spotted in the park at night and Lily would prefer if Herman would stay home. What she doesn’t know is that the monster is Herman!

Marilyn’s boyfriend, Tom Daily, invites the Munster clan to a masquerade. Eddie remains at home with Mrs. Morton as his sitter. Marilyn goes as Priscilla, Lily is Little Bo Peep, Grandpa is Napoleon and Herman is King Arthur in a suit of shining armor.

Leo Durocher, manager of the Los Angeles Dodgers, needs a power hitter for his team. When he gets conked on the head by one of Herman’s line drives from seven blocks away, he believes he has his man. He tracks Herman down and asks him to try out for the team. After Herman demonstrates his powerful force as a batter, Durocher comments: “I don’t know whether to sign him with the Dodgers or send him to Vietnam.”

Herman and Grandpa overhear Lily and Marilyn talking and somehow get the idea that Lily is pregnant. What’s really happening is Dr. Dudley’s son, Elmer, is coming to stay with the Munsters while Dr. Dudley and his wife are on vacation.

The gas company wants to run a pipeline 25 feet under the Munsters’ house. However, at that depth it would run through Grandpa’s dungeon lab...

Herman wants to go to a reunion with his army friends. Unfortunately he can’t seem fit into his uniform. Lily doesn’t want him to go, but decides to make a deal with him. If he can lose enough weight to fit into the uniform, he can go...

Thanks to a recommendation from an investigator of The Board of Education, Eddie is in danger of being expelled from school. The only way he can stay is if he makes an excellent project for the school’s Science Fair, so Grandpa helps him make a robot.

Herman becomes a professional wrestler called The Masked Marvel. After he shows that he has superhuman strength to a friend of Eddie’s who is the son of a pro wrestling manager. Herman uses the extra cash to save for Eddie’s college education. However Herman is so nice and gullible his opponents can take advantage of him.

Herman has a twin brother Charlie who is a con-artist. He comes to town and ends up stays at the Munster home, which doesn’t make Herman too happy. Charlie claims to have made an invention that takes uranium from seawater, he’s looking for an investor. Herman thinks that the whole thing is a scheme to get a Lily’s $5000 inheritance, he ends up being right.

Grandpa is feeling lonely and depressed so he contacts a matrimonial agency to find a mate. The agency sends over a nice looking elderly woman who find Grandpa to be delightful. She turns out to be the Black Widow: she makes her living by marrying her suitors, getting them to sign a life insurance policy naming her as beneficiary, and then murdering them.

After going to the car to find something Herman falls asleep in the back of his car with the keys in the ignition. The car is then stolen by bank robbers who don’t know that Herman is sleeping in the back seat. When Herman wakes up he wanders into their hideout and is thought to be Big Louie, a gang member who has taken twenty years of beatings in the boxing ring. Herman winds up as an accomplice in a bank robbery.

Marilyn has insomnia and in a attempt to cure it, Grandpa accidentally gives her a Sleeping Beauty potion instead. Now Marilyn can’t wake up unless she has been kissed by a prince. Lily and Herman advertise for a prince in classified section the newspaper, but this only attracts a couple of out-of-work actors. Meanwhile, Grandpa is negotiating with an oil company for the rights to use his magic pill that turns water into gasoline.

The Munsters have been chosen by Event Magazine as the average American family. Grandpa is insulted by being labeled “average”. He disappears, jeopardizing the family’s photo opportunity and the large amount of prize money that came with it. When a journalist and photographer arrive at the Munster home, Herman and Lily think they are burglars.

Grandpa feels neglected and decides to depart the Munster Family. In the beginning Lily and Herman believe this is just a ploy to get attention and they let Grandpa leave, expecting he’ll soon come back. Shortly afterwards, they begin to miss him and try to track him down. The find out he’s doing a magic act at a local nightclub.

Lily thinks that Herman has lost all his savings through a bad investment – when in fact he loaned it to her brother, the Wolf Man. She decides to build-up the family’s funds by taking a palm-reading job in a tea room. In a plot twist Grandpa and Herman suspect that Lily is sneaking out of the house to have a love affair.

Herman takes the family on a camping trip in a national park. After a dinner by the campfire, Grandpa hears the howls of the wolves and remembers his days in the old country. The next morning, Grandpa is missing. Lily realizes that he changed himself into a wolf to roam the woods with his canine friends. When she hears a news report about the capture of a rare Transylvanian wolf, Lily goes to the authorities to reclaim her father.

Herman goes to the dean’s office of Marilyn’s college to straighten out a tuition matter. When searching for the office, he wanders into the gym and is mistaken for a student basketball star who is expected for a tryout. Herman amazes the coach with his superhuman abilities and is offered a contract to play for the college team.

When Herman fools around with a ham radio in Grandpa’s dungeon, he thinks he’s contacted Martians. But he is actually speaking to two kids who are fooling around with walkie-talkies and just pretending to be Martians. The kids think Herman is also a kid, and a stupid one too.

Eddie wants to quit school because all the kids there call him Shorty. Grandpa helps by fixing a potion to make Eddie grow six inches overnight. Instead, the potion causes the young Munster to grow a full beard and mustache.

Eddie needs an impressive pet to take to the school pet fair, but Spot, the fire-breathing monster, is too shy to come out of hiding. Eddie decides to take Igor the bat, but Igor is insulted by one of Herman’s wisecracks and flies away. Without Eddie’s knowing, Grandpa changes himself into a bat to impersonate Igor. This causes trouble when Eddie gives Grandpa to another student whose father wants to send him to outer space on a scientific mission.

When Herman and Grandpa go to the bank to make a withdrawal, they are mistaken for bank robbers and handed eighteen thousand dollars in cash. When Herman gets home and realizes the wrong he’s done wrong, he can’t rest until he returns the money. When trying to bring it back in the middle of the night, Herman and Grandpa wind up locked in the bank’s vault.

In order to accompany Marilyn to her school dance, Herman decides to take dancing lessons. He goes to Happy Havemeyer’s Dancing School, where he is suckered into signing a ten-year contract for 1500 lessons (at $7.50 a lesson). Herman is under the wrong impression that he is going to become a dancing instructor for the school.

Herman goes out each night in order to practice becoming a real detective. Lily thinks he’s having an affair with another woman and hires the same detective agency Herman is working for to have Herman followed. In a Plot twist Herman gets the assignment to follow himself.

After Herman attends an office party that goes on until the wee hours of the morning, Lily locks Herman out of their bedroom and makes him sleep on the sofa. When they are unable to reconcile, Lily and Herman each see a marriage counselor independently.