

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