When Mork babysits Mr. Caruthers' daughter, Louise, she accidentally gets transformed into a Cave Ork and disappears. As Mork and Mindy desperately scramble to find Louise, Hamilton makes his way to Mr. Caruthers to rat them out.
When a car that Fonzie was working on is stolen, Squealy has the Fonz imprisoned, so Laverne and Shirley drag Squealy on a quest to capture the real criminal.
When Mork, Mindy and Eugene go to the circus, the evil ringmaster kicks them out and steals Mork's dog, Doing. The trio sneak back in disguised as clowns and mount a rescue for the Orkan pooch.
Squealy, Laverne and Shirley board a boat to obtain photographic proof of a two-headed swamp monster, and it isn't long before Fonzie and Mr. Cool arrive to offer assistance.
Orson instructs Mork to learn about love, so he gets some lessons from Eugene. Meanwhile, Mindy and Hamilton get cast in the school's production of Romeo and Juliet.
When a movie company comes to the military base, Laverne and Shirley masquerade as stuntmen in hopes of meeting star Lance Velour, but complications arise when someone on the crew steals top-secret government documents.
Laverne and Shirley decide to sneak off the military base, so they commandeer a jeep Fonzie's been working on, which sends them through a time warp into prehistoric times.
Orson sends Mork an Ork-Man video game for his birthday, but when it breaks, Mork uses his finger to fix it and accidentally brings the termite-like characters into reality.
M.A.B.E.L. is sent to sabotage the military games, and Laverne and Shirley receive the blame for the robot's shenanigans. But when M.A.B.E.L. gets broken, Fonzie is enlisted to give her a repair and tune-up.
On the morning of the school's Halloween dance, Mindy and Hamilton are elected King and Queen, so Orson conjures up a witch to go with Mork. Unfortunately, Broom Gilda takes a shine to Hamilton and bestows him with magical abilities.
Mr. McConnell relegates Doing to the back yard, so Mork devises a plan to get him back in the house by masquerading as a burglar and having Doing chase him away. Complications arise when Mork ends up in cahoots with a real burglar.
As Mindy prepares for a beauty contest, she notices a bug bite on her nose, so Mork uses his powers to heal it and accidentally turns her into a gorilla.
Mork splits himself into two people so he can simultaneously clean the McConnell's music store and attend Hamilton's party with Mindy. Unfortunately, one Mork's good, the other's evil, and it's the evil Mork who skips out to the party.
Mork prepared eggs for Orson which are filled with the essence of a variety of animals. At the annual Boulder Wild West Day, the rodeo animals unwittingly consume Orson's eggs and begin behaving uncharacteristically.
Orson sends Mork's parents to Earth when Principal Caruthers demands a meeting with them. Since Orkans age in reverse, they appear much younger than Mork, so a wealthy curmudgeon kidnaps them in hopes of finding the fountain of youth.
