Urkel befriends Lowell, an orangutan who has been abused through a series of laboratory experiments. At the precinct, Carl is exercising on a treadmill when he discovers it has been booby-trapped by a revenge seeker; the bomb hidden inside will go off should he step off the treadmill. He must rely on Lt. Murtaugh - and a little bit of luck - to disconnect the bomb's wiring before it explodes.
It's brains vs. brawn in a rope-climbing contest, as scrawny Urkel competes against loud-mouthed jock Alex for the rights to capture Laura's affections. Urkel knows he can't win the conventional way, so he devises a jet pack to help ensure his victory.
Laura wins the female lead role in the school production of "Romeo and Juliet," and looks forward to the kissing scene with her Romeo, Daniel Wallace. Then Daniel falls ill and the understudy - who else but Urkel - takes his place. Thanks to Urkel's clumsiness and being himself, the play turns out to be a disaster.
Urkel repeatedly sleepwalks into the Winslows' bedroom to belt Carl over the head with a newspaper. Harriette gets an annoyed Carl to call over a hypnotist to see what's behind Urkel's behavior ... and Harriette is more than a little disturbed by the findings. Turns out Carl had yelled at him after the nerd accidentally broke his ship-in-a-bottle, then - unaware that he was listening in - told Laura he wished he'd go away for good. Carl eventually realizes he needs to apologize.
It's a case of puppy love for Laura when she falls head over heels for Carl's new rookie partner, Officer Mike Doyle. Carl's remarks about Laura playing grown-up - in front of Mike - don't go over too well.
Urkel annoys Carl with his prized Peruvian beetle. The bug gets loose and a spooked Carl kills it, to Urkel's horror. When Carl refuses to pay for the expensive bug, Urkel decides to see if a television small claims court judge agrees that it was more than "just a stupid bug."
Urkel creates a robot named after himself. But the robot soon develops a mind of its own and - after trapping its inventor in the closet - poses as the nerd and invites Laura over ... so it can have her all to itself.
Urkel and Laura are in the same boat as equipment manager for the basketball team and underclassman cheerleader, respectively. Urkel's talents on the court seem to go unnoticed by the coach ... until he is the only available team member left who hasn't become injured or fouled out; he winds up being instrumental in his team's winning rally. In Laura's case, she has to deal with snotty team captain Cassie Lynn, who insists on running the squad her way, even though her clichéd cheers aren't going over too well. Laura's cheers, however, really spark some crowd enthusiasm.
A street gang named the Dragons begin causing trouble at Rachel's Place, breaking things and sexually harassing employees; Carl arrives just in time to chase them out. That night, after closing time, the gang breaks in and heavily vandalizes the teen hangout. Everyone's anger grows when a bruised and bloodied Eddie arrives, announcing he was ambushed by the Dragons' gang members. Carl wants to take matters into his own hands, but Urkel reminds him that if he were to do that, he'd only destroy much more than his career. Urkel eventually agrees to go undercover as a ...
Urkel tutors a pretty girl named Vonda, a girl whom Eddie is looking forward to asking out. When she passes a test, Vonda comes on to the nerd, prompting him to conclude she has an easy reputation. Urkel helps set her straight, which is good for her ... but definitely not what Eddie was hoping for. Meanwhile, Carl is the butt of Lt. Murtaugh's jokes when he is asked to wear drag for a drug sting.
Urkel tries to tell Laura that potential boyfriend Daniel Wallace is bad news. Thinking his attempts to meddle in her life have risen to a new level, Laura tells Urkel never to speak to him again. Harriette finds out and warns Laura that she may not only regret her words, but that she'll surely grow "old and alone." That night, Laura has a dream whereby she is an elderly spinster while 90-year-old Urkel is married to a beautiful woman.
Urkel joins in on Carl's poker night, only for Lt. Murtaugh to take quick advantage and clean out the nerd. Eventually, Urkel gets his revenge by cleaning out the hustling, loud-mouthed lieutenant. Meanwhile, Harriette offers to help understaffed Rachel at Rachel's Place, but Rachel takes her sister's well-meant suggestions the wrong way.
Rachel becomes choir director at her church and soon drives everyone crazy with her micromanagement. She also unknowingly tests recent born-again Christian Urkel's faith when he wants to join the choir, despite his (decidedly) off-key vocal abilities. Estelle eventually sets Rachel straight
Eddie doesn't study for a chemistry test and convinces Urkel to help him cheat (by pretending to have a cold). When Urkel really does have a cold, he is caught giving Eddie the answers and - when he keeps mum about who he was helping to cheat - is threatened with expulsion. Meanwhile, Carl becomes the laughingstock of the precinct when he literally sleeps through a house burglary (thanks to the crooks using sleeping gas). One night, when Eddie and Urkel were confessing their misdeed to Carl, they fall asleep again - only for Harriette and Rachel to nab the burglars in...
Harriette's troubled cousin, Clarence, comes to live with the Winslows until he can straighten out. Instead of deciding to fly right, Clarence becomes a bad influence on Eddie and gets him and Urkel into big trouble when they are caught with a bunch of pretty girls ... and a stolen car! Eddie confesses and realizes he shouldn't have listened to Clarence, whom Harriette quickly becomes fed up with and kicks out of the house.
Estelle wants to share the stories of her late fighter-pilot husband and World War II's Tuskegee Airmen with her family, but nobody is interested. She decides that Eddie's American history class may be more willing to listen (particularly Eddie, after he sees how cool his grandfather was).
A variety of situations involving the gang and home-ec class: Urkel can't cook a lick (and of course causes plenty of accidents); snotty Cassie Lynn finds she can't always be a cover girl all the time; and Waldo learns he may just be good at something after all.
Urkel again tries to intervene in Laura's budding romance with Daniel Wallace, whom the nerd has learned is nothing but trouble. Laura believes Urkel is meddling in her love life and tells him to go away. Then Daniel sneaks into Laura's room and, when he tries to kiss her and she pushes him away, he calls her a baby - just like Urkel had warned. Eventually, Daniel is chased away and a shaken Laura breaks down in her parents' arms.
Laura runs against Cassie Lynn for class president. Cassie Lynn is determined to win any way she can - even if it means publishing photos of Laura and Urkel caught in a compromising situation (he actually was trying to brace Laura, who had fallen from a ladder). So, Urkel decides to fight fire with fire.
Urkel convinces R&B singer Johnny Gill to serenade Laura in the Winslow's living room. Meanwhile, Carl and Harriette try to enjoy their second honeymoon at a resort that's a little too cold for comfort.
Laura had enough problems trying to give Urkel the brush-off. Now, Waldo is the one who's head over heels in love with the Winslow girl ... especially after she tried to encourage down-on-his-luck Waldo.
Urkel is invited to stay with the Winslows when the nerd's parents go out of town ... and quickly causes plenty of chaos. He drives Laura's study partner away, convinces Richie to get into a fight with a preschool bully, and accidentally vacuums up Lt. Murtaugh's fish that Carl was baby-sitting.
A reprogrammed Urkelbot is sent to fight crime, and proves to be instrumental in foiling a serial convenience store robber. Meanwhile, the women find (to their horror) that a new shampoo has caused them to go bald.
Urkel, Eddie and Waldo go on the teen dating show "Dudes," which Laura insists is raunchy and sexist. Urkel easily wins a date with one of the female contestants, but instead uses his live TV opportunity to reaffirm his love for Laura.