The infection rapidly spreads through the household. Tina gets it after high-fiving Gene; Bob gets it after wearing shoes Gene had "scratched" himself with; and Linda eventually succumbs despite her initial denial.
Louise is the only family member who remains uninfected, becoming increasingly paranoid and physically distancing herself from her "wormy" family. Linda, driven by her obsession with the symphony, eventually breaks down and destroys a "hamster slide" the kids built in the living room while chasing Louise.
The episode follows Linda Belcher’s desperate attempt to take the family to the symphony for "free admission night" to prove they are a sophisticated family. Her plans are derailed when a breaks out, starting with Gene.