Carl spends the next few days walking a mile in Urkel's shoes, while Myra explains herself to Stefan. Eventually, Stefan (who has thankfully kept Urkel's scientific genius, albeit in a slightly-slower manner) repairs the machine, and has him changed back before he can wreak any more havoc on the Winslow household. Carl eventually realizes he could have spared everyone so much grief by following his wife's advice and getting glasses. Soon after, on Stefan and Laura's date, Stefan says he did not recharge and soon reverts back to Urkel.
After Steve made improvements on his Transformation Chamber to remain as Stefan for extended periods of time, Myra grows angry and tampers with the chamber hoping to get her perfect man back. Meanwhile, Carl has balked at taking Harriette's advice to see an eye doctor to get some glasses. He takes Eddie's advice and gets permission to from Stefan to use the chamber. Myra soon realizes that it's Carl in the chamber and confesses to tampering with the machine by switching the dial from cool to nerd. Stefan tries to stop the chamber, but it breaks. Myra realizes what she has done when Carl Urkel comes out of the chamber.
Carl continues behaving as a nerd until his normal self regains control of himself. Stefan realizes he didn't stop the machine in time because he's half-nerd, half-Carl. The nerd side of Carl asks him if it makes him a "Narl" and laughs before the normal side of Carl takes control again. Myra apologizes for her actions, not realizing he was in the chamber, and she feels like a worm. Nerd Carl goes into the anatomy of worms. Stefan is astonished but the normal part of Carl has no idea how he knew that. He begs him to help fix him by repairing the machine. Stefan agrees, but he now needs parts to fix it because most have been broken. Nerd Carl readily gives him money and pleads with him to fix it soon. Stefan tells him to give him 24 hours to fix it, while remarking to himself that the real Carl would've asked about the costs. Carl must break the bad news to Harriette and no sooner he leaves, he breaks a vase.
Harriette is baking a cake when Carl comes home. She thinks he's doing an impression of Steve until she discovers that he's stuck as a nerd. Normal Carl explains he's half-Carl and half-Nerd. He don't know when he'll be back to Carl and when he'll be the nerd. She tries to take him to Stefan to get in the chamber, but Nerdy Carl takes her back home and reveals the chamber is broken. Eddie and Laura soon discovers what happened to their father and tries to stop him from going to work. Nerdy Carl soon sits on Harriette's cake, causing her to behave similar to her husband.
The next day, Stefan is fixing the chamber in the basement of his house when Carl comes to visit him via the elevator. His day isn't looking any good because he's been spending time not only talking more like a nerd, but indulging in things similar to Steve (eating cheese, listening to the Bulgarian Women's Choir and ironing his own underwear). Stefan realizes the nerd genes in Carl have unfortunately accelerated and confesses that his repair on the chamber is going slow because he may be cool now, but isn't as smart as he used to be. Nerdy Carl soon points out that the crystal transformer was put in the wrong way and pulls it out to prove it. Pretty soon he annoys Stefan to no end and he's sent home, implying that Urkel may now have seen what life is like as Carl.
A week passes and Stefan has finally fixed the chamber. He calls Harriette to let her know that the chamber has been fixed and before he can arrange for time of day, she speedily shows up with Nerdy Carl. She tells Stefan she's eager to get him fixed because she had to sleep with him for a week. Carl steps into the chamber and is back to normal. To make sure it's him, Stefan tests him by claiming Harriette has a new outfit on. Carl mentions it looks expensive and asks for the costs. Stefan and Harriette are relieved that it's actually him and not the nerd version. Carl confesses that he took Eddie's advice and went to Stefan to use the chamber to fix his eyesight because he was afraid of how glasses made him look old. Harriette admonishes him for not listening to her in going to an eye doctor and get glasses. Carl agreed and never thought he'd come out of the chamber similar to Steve. He realizes that Harriette's advice was best heeded and decides to set up an appointment with an eye doctor to get glasses, while planning to admonish Eddie for his terrible advice. Stefan at that time also realizes why he himself doesn't accept himself for who he is and whom he really isn't.
During Laura and Stefan's date, they have a photo taken before eating. Stefan in depression tells Laura that he no doesn't have the feelings for her anymore like he did before because he wasn't loving himself for how Steve has created him to be and realizes that he must go back as Steve. Laura tries to convince him not to. However, Stefan reveals he didn't recharge to maintain as himself before their date and slowly reverts back to Steve. Maintaining himself, Stefan bids Laura farewell and leaves before he causes more damages as Steve switching back and forth Steve and Stefan but without the antidote. While switching in between Steve and Stefan, he accidentally spills food on a woman's dress and stops switching and as Steve, he looks on and asks her "if he did that". The woman angrily gets up from her table without answering him and chases Steve out the restaurant in rage. Laura resolves to have him back soon after getting a photo of them together.
During the end credits, Mother Winslow dreams of using Steve's transformation chamber and comes out very young and beautiful to impress Fletcher. She soon wakes up from her dream.
- Reginald VelJohnson as Carl Winslow and 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, credit only)
- Jaleel White as Steve Urkel and Stefan Urquelle
- Shawn Harrison as Waldo Geraldo Faldo
- Garcelle Beauvais as Young Estelle Winslow (dream)
- Lisa Ann Grant as Photographer at Amore' (credited as Lisa Grant)
- This is the second time a Winslow has experienced like akin to Steve Urkel. The first time was in "It's Beginning to Look a Lot Like Urkel", when Laura experienced life as Laura Urkel.
- This episode marks Garcelle Beauvais' third appearance in the series, portraying a younger Estelle Winslow in a dream Estelle had. She previously appeared in Season Three's "Old and Alone" as Lulu, a woman who married Urkel in a dream, as well as a woman at the mall in Season Five's "Scenes from a Mall". She made her final appearance in Season Seven's "A Ham is Born" as Nicole Moses.
- Early scripting for the episode had Carl coming out of the Transformation Chamber as Carl’s version of Stefan instead of Steve. The episode would see Harriette ironically disliking this version of Carl due to his changed personality and other women being attracted to him. The ending however, would have remained largely the same. This plot was changed as Carl playing Steve was believed to be far more comedic at the time.
- Stefan: Good lord, you're a nerd.
- Carl: Espousing camaraderie and human interaction makes me a nerd? If so, then I plead guilty.
- Stefan: That's it, go home!
- Carl: But I don't wanna...
- Stefan: Go home!
- Carl: But I was just...
- Stefan: Go home, go home, go home!
- Carl: I don't have to take this, I'm going home.
- Harriette: Let's do it, and hurry. I had to sleep with this man last night.
- Carl: Yeah, I'm eager, too. I was denied my husbandly rights.
- Stefan: Hey, with a woman as beautiful as Harriette that's a terrible loss.