Harriette asks Carl to go see an eye doctor after he complains about having problems seeing. However, he balks at the idea and takes Eddie's advice by asking Urkel for some help. Urkel, meanwhile, has been perfecting his "Boss sauce" serum and transformation chamber to enable him to be Stefan all the time. Carl asks Stefan to let him step into the transformation chamber to fix his eyesight problems. However, a jealous Myra – wanting to snare herself a certain nerd – tampers with the machine by switching the dial thinking Stefan will use it to change back into Steve. Unbeknownst to her, Carl is really inside and once she learns the truth, she tells Stefan to stop the chamber. Sure enough, the chamber is broken and Myra realizes what she has done when Nerd Carl (instead of Carl Winslow) steps out!
Myra doesn't want Steve to change a thing about himself, while Laura sees Stefan as a perfect ten in her eyes. Urkel tweaks his chamber to allow himself to be Stefan all the time, much to Myra's chagrin.
Meanwhile, Carl is complaining about his dwindling eye sight since he's getting old. However, he balks at Harriette's recommendation to just go to the optometrist and get his eyes checked for glasses. One night after a mishap at dinner in Chez Josephine's, Mother Winslow admonishes him for nearly destroying her favorite 4 star restaurant and asks him to get glasses. Carl refuses still and Eddie is perceptive in his refusal thinking that if he were to get glasses, he'd be admitting that he's getting old. He suggests that Carl asks Stefan to use the transformation chamber to fix his eye sight. When Carl gets skeptical and asks why, Eddie reveals that Stefan has perfect vision. When he mentions that Steve couldn't see without glasses, this convinces Carl of a 2nd option. He takes Eddie's advice and asks Stefan to let him use his chamber to fix his eye sight, unaware that advice is the one he will forever regret.
However, Myra misses her perfect Steve and decisively tampers with the chamber as revenge against Laura for her misery. Resetting the chamber, she thinks that Stefan will use it to return to Urkel and ensnare him. Unfortunately, she overhears Carl thanking Stefan in using his chamber, which worries her. Once Carl is in the chamber, Myra quickly tells Stefan to stop the machine because she tampered with it. When Stefan asks her why, Myra revealed she rewired the transformation chamber and it was reset to nerd, rather than remain on cool. He tries to stop it and it circuits short fuse. After Stefan opens the door, Myra realizes what she has done when Nerd Carl steps out of the chamber.
Adopting a nerd personality, Carl comes out as in a stereotypical nerd fashion, hitched up underwear, pocket protector, sagging pants and suspenders. Stefan asked Carl if he's still there. Nerd Carl that he hopes so and attempts to pull his pants up, but gives himself a wedgie. He laughs and snorts while Stefan is embarrassed and Myra is horrified by what she did to Carl.
- Reginald VelJohnson as Carl Winslow / Nerd Carl
- Jo Marie Payton as Harriette Winslow (credited as Jo Marie Payton-Noble)
- Rosetta LeNoire as Estelle Winslow
- Darius McCrary as Eddie Winslow
- Kellie Shanygne Williams as Laura Winslow
- Bryton James as Richie Crawford (credited as Bryton McClure)
- Jaleel White as Steve Urkel / Stefan Urquelle
- Shawn Harrison as Waldo Geraldo Faldo
- Michelle Thomas as Myra Monkhouse
- Lisa Grant as Photographer
- Victor Wilson as Waiter
- This is the first two-part episode of the series.
- As of this episode, Michelle Thomas joins the main cast and is included in the opening credits theme.
- Myra's full name is revealed to be Myra Boutros Boutros Monkhouse.
- This marks the first time that the Urkel Transformation Chamber is sabotaged.
- Eddie': Too bad you can't pull a Stefan.
- Carl: A what?
- Eddie: Well, Stefan Urquelle doesn't need glasses, but when he was Steve Urkel he couldn't see zip without 'em.
- Carl: That's right.
- Eddie: Sounds like what you need is a transformation chamber.
- Stefan: Myra, what have you done?
- Myra: Okay, I rewired the chamber, and istead of cool, it's set on nerd.
- [Stefan tries to stop the chamber and the chamber ends up being busted. When the door opens Carl appears dressed up as Steve normally dresses with his glasses]
- Nerd Carl: Hi-diddly-dee. It's me.
- Stefan: Carl, is... is that you?
- Nerd Carl: I sure hope so. 'Cause I'm wearing his underwear.