When Homer learns that kitchen grease waste can be sold to rendering plants, he becomes obsessed with the idea and decides to make a grease fortune. At school, Lisa is asked to show a new student named Alex Whitney around. While Lisa is interested in dolls and jacks, Alex is like a mini-adult, wearing perfume and going on shopping excursions. Soon, Alex has become a hit with Lisa's friends, and Lisa feels left out.

Alex convinces Principal Skinner to change the school's annual "Apple Pick" to a dance. Lisa learns that everyone is bringing a date. Feeling as if she has to be like Alex, Lisa becomes desperate to get a boy to go with her. While bullying Milhouse into dropping his date and taking her instead, Lisa realizes she's becoming someone she doesn't want to be. She sadly decides to go without a date.

At the dance, all of the boys stay separate from the girls, and nobody has the nerve to ask anyone to dance. Alex doesn't understand, but Lisa explains that they're all acting like kids because they are still kids. Meanwhile, Homer and Bart sneak into the school to get the kitchen stove's grease. With a hose sucking the grease out of the stove, they're caught by Willie who attacks Homer in order to protect his retirement grease. While pummeling Homer, Willie causes a massive grease explosion. Grease rains down uponthe dance via the air ducts and the kids start toi play with it like snow. Alex is initially disgusted, but soon she can't help but start playing in the grease like the rest of the kids.