In the episode, the fourth grade students of Springfield Elementary School decide to spike Edna Krabappel's coffee in order to teach her a lesson after she takes away their cell phones.
Although Vaughn is a hip young teacher who impresses the students, Bart is plagued by guilt and tries to get Edna hired back.
Edna Krabappel's optimism is crushed when she sees her students distracted by their cell phones, so she takes the devices away.
Bart visits Edna and feels guilty seeing her moping in front of the television and plots to get her rehired.
He meets Milhouse at a bookstore where they buy a self-help book, which professes to have the answer to help someone achieve their dreams.
However, when Bart inadvertently confesses he had the idea to spike her coffee and is responsible for getting her fired, Edna is furious, telling him that her real dream was to be a teacher and is now facing debt and competition from other muffin stores.
Skinner is pleased that Bart was honest and agrees to punish him but he cannot rehire Edna when Zack is doing a good job.
They are disrupted by a drunk Zack who secretly mixes vodka in his own drink and mocks the schoolchildren.
She responds by making every student in the class eat a stale muffin as payback for the liquor incident.