Bart plasters unflattering graffiti images of Homer all over Springfield. They catch the eyes of established street artists Shepard Fairey, Ron English, Kenny Scharf and Robbie Conal, who catch him in the act, and they invite Bart to exhibit his work at a gallery show of his own. Meanwhile, a new health-food superstore threatens to put the Kwik-E-Mart out of business.
As a birthday gift for Marge, Homer buys a blender designed by television chef Paula Paul. He goes to a health food store called Swapper Jack's, where Paula is giving away autographs, to have Paula sign it. Homer is impressed by the store and says he will not be shopping at the Kwik-E-Mart any more. Apu, who is there to spy, overhears Homer and the two engage in a fight until the security guards grab hold of Apu and take him away. At the signing, Homer tells Paula that Marge is a big fan of hers. Paula chooses that she will call Marge live during her upcoming show to wish her a happy birthday. Meanwhile, Bart gets his mother a rabbit for her birthday. The rabbit chews through the phone lines in the Simpsons' home, causing Marge to miss Paula's call. Paula becomes irritated at Marge for not answering the phone as she embarrassed herself on her show. Homer then punishes Bart by locking him in the rabbit's cage.
To get revenge on Homer, Bart goes around Springfield spray-painting graffiti of Homer's face and the word "dope". When his work appears on the television news, it encourages Bart to create even more graffiti in the town. Street artists Shepard Fairey, Ron English, Kenny Scharf, and Robbie Conal encounter Bart one night when he is making some graffiti. The four tell Bart that they are impressed by his work and would like to showcase his art in a gallery show, at first Bart is unsure, but Bart remembers how Homer treated him, and then agrees. Meanwhile, the Kwik-E-Mart suffers because of the competition from Swapper Jack's. Apu ends up attempting to rob Swapper Jack's in a desperate measure, but the cashier (Snake Jailbird) convinces him to hand over the gun. Later, Apu is about to shut down the Kwik-E-Mart when his wife Manjula tells him that Swapper Jack's is closing because it was discovered they were selling monkey meat imported from Brazil as chicken.
Homer initially refuses to attend Bart's show because he discovers the artwork is an insult to him, but changes his mind after Bart apologizes and writes "I'm sorry" on the hood of Homer's car. At the show, Chief Wiggum and the Springfield Police suddenly appear to arrest Bart for making graffiti throughout the town. It is revealed that the gallery show is a sham and that Fairey is an undercover officer who helped the police identify Bart as the graffiti artist that had been spray-painting Springfield. Since Bart is just a boy, he is not sent to jail. Instead, he is punished by once again being locked in the rabbit cage. When Bart tells Wiggum that he has to go to the bathroom, Wiggum covers the cage with the blanket and finds Bart gone when he removes the blanket from the cage.