Springfield is having a parade in homage to the city's founder Jebediah Springfield. During the parade, Bart activates a fire engine's water cannon, soaking Chief Wiggum. As a result, the Springfield Police Department got into a battle against the volunteer fire department which ended with a SWAT tank losing control and destroying the Kwik-E-Mart, injuring Apu and Sanjay. At the hospital, Sanjay reveals that he wants to retire from his job at the Kwik-E-Mart and gave his share of the store to his son Jamshed Nahasapeemapetilon.
Seeing Bart's prank consequences, Homer decides that Bart has gone too far and makes him promise to never prank again. Milhouse tries to bring the old Bart back, but he resisted dropping a beehive on Superintendent Chalmers' crotch and releasing the handbrake on Principal Skinner's cherry-picker. But his new personality came with benefits, as now he's getting better grades. As a result, Bart's having a closer bond with his younger sister Lisa as now he understands her point of view for not having any recognition at all for her achievements.
Six weeks after the incident, Apu goes see what they've done with the Kwik-E-Mart only to find at its place the Quick & Fresh, a store that sells natural products run by Jamshed (who is now called Jay). At the store's restroom, Jay explains that Apu has an addiction to scratching lottery tickets. Because of that, he's the owner of 80% of the store. Later, Moe and Apu are talking about what happened to his store. Jay, who's already angry at his uncle for being a stereotype, fires Apu from his job. Apu is so depressed that he goes to Moe's Tavern where Moe convinces Homer to turn Bart into a prankster again for him to pull a prank on Jay so Apu can have his store back.
Bart, who comes back to his old self Clockwork Orange-style, decides that the best prank would be to turn the Quick & Fresh light switch off for thirty seconds. As none of the products have conservants, everything will get rotten. He's interrupted by Lisa, who reminds him that after he stopped pranking, they love each other even more. Bart misinterprets the expression "unconditional love" as a sign he can do anything he wants and still be loved by his sister, so he cuts the store's power for a few seconds.
Inside the store, all the products start deteriorating, scaring the customers away. When he turns the power back on, two massage stones collide, producing a spark that leads to a major fire. As the firefighters used all their water and foam against the police officers on the parade, they have nothing they can extinguish the fire with and the store is completely destroyed by the flames. Later, Apu apologizes about what happened to Jay, but he also found a 'The Big Bang Theory scratching ticket in the middle of the debris. He scratches it and wins a million dollars—enough money to buy his store back and rebuild the Kwik-E-Mart.
In the final scene, Mayor Quimby plans to have Chief Wiggum use a tank to destroy the Jebediah Springfield statue. Chief Wiggum fires at the statue only for projectiles to be deflected enough to destroy the tank much to Mayor Quimby and Chief Wiggum's annoyance.