Lisa freezes during a federal school-assessment test; Homer tries to prevent accidents from happening after he forgets to pay the insurance bill; and Skinner accompanies Bart and other underachievers on a trip to Capital City.

One morning Homer and Marge celebrate the “new year” when summer finally ends, and Bart and Lisa begin their new school year. As the family eats breakfast, Marge gives Homer an envelope containing an insurance payment. Homer promises to mail it. Later, at Springfield Elementary, Principal Skinner announces that at the end of the month the school will participate in the Vice-President’s Assessment Test. The results will determine how much money the school will receive from the federal government for years to come. Everyone from Mrs. Krabappel to the gym coach performs drills to make sure the students know the test’s questions and answers. When the day of the test arrives, Lisa asks Bart about one of the questions on the practice test. Bart says he didn’t bother answering the questions: he wrote the words “Slurp My Snot” by filling in ovals on the answer sheet. When Bart arrives at school, Skinner informs him he got a perfect score on the practice test. As a result he and a group of other “perfect scorers” — Nelson, Ralph, Jimbo, Dolph, and Kearney — are exempt from taking the real test, and will be transported by helicopter to a pizza party at a bowling alley. The helicopter turns out to be a cardboard façade. Bart and the other kids realize why they’re trapped aboard Otto’s bus: they’re underperformers who’ll skew the test results in a negative fashion. Superintendent Chalmers tricks Skinner into going with them to Capital City.

As Homer drives up to the guard gate at the nuclear-power plant, he realizes he never mailed the insurance payment Marge gave him. Homer drives to the insurance company building only to discover that it will be closed for another six hours. He drops the payment into a mail slot, and leaves worrying about a catastrophe that could wipe out everything he owns. Meanwhile, at school, Lisa frets about Bart’s test score. She can’t understand how her brother performed so well. The anxiety causes her to freeze once the test gets underway. On the bus Ralph announces that he has to use the bathroom. Otto pulls over at a rundown downtown gas station. When Skinner and the boys step out of the restroom, they discover that the bus has been stripped by vandals.

Homer returns home and tells Marge they must avoid all accidents and injuries until three o’clock that afternoon. Marge tells Homer he can help host her book club. As the book club gets underway, Homer imagines a series of catastrophes; including Helen Lovejoy’s hair catching on fire, and Mrs. Skinner getting struck with an axe. Skinner, Otto, and the boys walk the streets of Capital City. Suddenly Skinner sees Ralph sitting on a garbage barge floating on a nearby river.

As three o’clock approaches, Homer realizes he only has to keep an eye on the book club women for ten more seconds. He watches in horror as Mrs. Skinner drops a knife. Homer dives, and catches the knife before it slices into Mrs. Skinner’s foot. He then sees Lindsey Naegle’s scarf being sucked into the blades of a table fan. This sets in motion a series of events ending with Mr. Burns being hit in the head with a knife. As Mr. Burns bleeds, Homer realizes the accident occurred one minute past 3:00; he’s insured. Skinner scribbles a note asking a crane operator to rescue Ralph from the barge. Skinner balls up the note, and using Bart’s slingshot, shoots it toward the crane operator. Unfortunately the wadded-up ball hits the crane operator in the head, knocking him unconscious and causing grand pianos to crash near Ralph. Thinking quickly, Skinner jumps onto the container holding the grand pianos, and starts to run in a circle. The container turns, preventing Ralph from being squashed by a piano. Later Skinner entertains the boys by reading The Adventures of Huckleberry Finn aloud. When Skinner returns to Springfield Elementary, he labels the test “a joke,” and tells Chalmers it’s their duty to educate, not turn students into automatons. The test is thrown out. Lisa, who froze during the test and saw her future evaporate, is overjoyed.