While preparing the school's auditorium for the Junior Prom, Laura's date, Jimmy, is a an arrogant, controlling and possessive jerk who thinks that Steve Urkel is his competition for her love. She tells him that he's wrong, and they're friends.
At the house, Harriette tells Carl that she, Laura and Estelle had gone shopping all day for junior prom dresses. Carl liked the first dress that she had on, a green, off the shoulder dress until he nealy gets a heart attack when he learns the dress was over $300. Harriette tells her to change into the other dress, and he asks her how much it was. When she tells him it was $180, Carl calms down and thinks it's a nice number. Estelle accuses him of being a cheapskate as Laura comes down in a blue dress. He instantly likes it, but Harriette is concerned that it may be on the short side. Carl tells her to calm down because it's perfect and it's not too revealing. He leaves and she's relieved that her mother's plan worked. Harriette tells her to go upstairs and put the green dress back in Rachel's closet.
Meanwhile in the kitchen, Eddie warns Waldo that setting his younger sister, Quesidilla(which he explains her name since she was born in Taco Bell), up with Weasel would be a bad idea because he's been known to like a girl for her looks and takes his dates for granted. Waldo agrees to keep an eye on Quesidilla and Weasel for a while.
Later on, Steve comes over to the Winslow home and asks Laura for some advice on how he can take Myra out to their school's Junior Prom since she goes to a different school. She tells him the advice he needed to hear and misses him asking her out. Urkel quickly remedies the situation by asking Laura out, and she says no. That relief is short lived when Jimmy arrives and orders her to stop seeing Urkel at once.
At the prom, Portrait is performing and the students are dancing. Maxine was excited that Waldo knew them, but he can't reveal which one is his cousin because of a deal they made that as long as he never reveals that they're related, he'll do anything for him. Weasel shows up with Quesidilla in arm and he warns him that he'll keep his eye on him if he does anything bad to her. A student imforms the crowd that Urkel is on the way, and they groan in disgust. However, he has a date and they're shocked. Steve comes in and impresses the crowd by bringing the sweet, intelligent and beautiful Myra to the dance as his date.
The prom continues with Portrait singing Day By Day and Steve is dancing with Myra amongst the crowd. Waldo tries to break them up, but when he learns that Weasel had been a gentleman to Quesidilla the whole time, he realised Eddie was wrong and left them alone. Carl and Harriette who had gotten of work early, comes to the dance for Laura because they forgot to take her picture. Steve talks to Myra about the final dance which involves him dropping balloons with his new invention. Later on, he's seen talking to Laura and he's having a great time with his date. She's glad for him. When Jimmy bans her from talking to Steve again, Laura tells him off that he has no right to tell her who she can't be friends with. She mentions that even though Urkel is annoying, he always respects her as a friend and it's why he has a date. She also tells him off that their date is over and Jimmy tries to chase after her.
Eddie says hello to Portrait until one of the members says "'Sup". Steve instantly goes to the fourth member and tells him that he is Waldo's cousin. He's embarrssed by the whole thing and Urkel comforts him. The last song is underway everyone is seen with they dates, except Laura who is seen with Carl and Harriette. So far it goes good with the first and second drop of the balloons. But when the last set goes wrong and the water sprinklers go off, the crowd blames him, except Myra.
Later on at the Winslow kitchen, Steve is in his pajamas and blames himself for turning the last dance into a three-ring, water circus. Laura told him that it could've happened to anyone else and thought Myra was upset about it. Urkel reveals that she wasn't that she kissed him and encouraged him not to let crowd get him down because even Einstein had his set backs as well. He thanks Laura for standing up for him, but she revealed she did it not only for him, but herself as well. They hug in the end.