Lisa’s toil and sacrifice on the elementary school’s yearbook pays off when shipments arrive from the printer. But Lisa’s pride turns to disappointment after she realizes no one at school wants to sign her copy of the book. Meanwhile, Flanders gives Homer access to his beach house in Pwagmattasquarmsettport. The Simpsons pack their bags and prepare for summer vacation. Lisa, however, deliberately leaves her clothes behind, determined to create a new, less nerdy image of herself.

Once the family settles in at the beach house, Marge takes her daughter shopping for new clothes. Lisa chooses hip, stylish attire instead of her usual drab outfits. Later, Lisa encounters some kids hanging out beneath a pier. Aided immeasurably by her new look, and consciously avoiding the pitfalls of her superior vocabulary and intellect, Lisa succeeds in making friends with Erin, Rick and Dean. But Bart’s attempt to befriend the same group of kids fails miserably when he tries too hard to impress them. Meanwhile, in anticipation of the upcoming Fourth of July holiday, Homer purchases a powerful firecracker. But he ignites the bomb using the flame from a gas stove, catching the fuse too close to the explosive. In a panic, Homer shoves the bomb into Flanders’ dishwasher, causing water to flood the house.

Jealous of Lisa’s new-found popularity, and convinced his sister copied his personality, Bart plots revenge. He shows the beach kids Lisa’s yearbook and points out all the nerdy, unhip things his sister did at school. Mortified, Lisa runs off, crying. Furious at Bart for ruining her vacation, Lisa exacts her own revenge at a carnival. When she returns to the beach house, she’s greeted by her friends, who have decorated the Simpson car with hundreds of beautiful seashells in her honor. Lisa is genuinely touched by their gesture of friendship. The kids explain how much they like Lisa for who she is—not who she was.