While riding the bus to school, Milhouse shows Bart his new fortune-telling toy, a Magic 8 ball. Bart asks the ball whether he and Milhouse will still be friends by the end of the day, and the ball predicts they will not. Both are puzzled by how this could happen. A new girl from Phoenix, Samantha Stanky, starts at Springfield Elementary School the same day, and Milhouse instantly falls in love with her. To Bart's dismay and anger, Milhouse and Samantha start a relationship and, rather than playing with Bart after school in his treehouse, Milhouse brings Samantha with him and spends the entire time hugging and kissing her. They ignore Bart, leaving nothing for him to do but leave in tears.
Milhouse and Samantha spend all their free time together. Jealous and feeling excluded, Bart reveals their relationship to Samantha's father. Before Samantha can explain, Mr. Stanky rushes to Bart's treehouse and sends her to Saint Sebastian's School for Wicked Girls, an all-girls convent school run by French-Canadian nuns. After seeing Milhouse heartbroken, Bart begins to feel guilty for what he did. Bart and Milhouse start fighting after Bart reveals that he snitched to Samantha's father. After calming down, the two boys visit Samantha at the convent school, and Bart apologizes to her. Samantha says she loves Saint Sebastian's, but she still has feelings for Milhouse and gives him a goodbye kiss, despite knowing it is violating the school rules.
In the subplot, Lisa worries that Homer's obesity will lead to an early death. On Lisa's suggestion, Marge orders a subliminal weight loss tape for Homer. However, the company is out of weight loss tapes and sends Homer a "Vocabulary Builder" tape instead, unbeknownst to Marge and the family. Homer puts on the headphones in bed and falls asleep. When he wakes up, he is suddenly articulate, but ends up eating more food than ever. Once he realizes the tape has not helped him lose weight, Homer gets rid of it and his vocabulary quickly returns to normal.