In order to get back at his dad, Bart goes undercover as a graffiti street artist and plasters Homer's unflattering image all over Springfield. But one night, Bart and Milhouse get caught in the act by established street artists Shepard Fairey, Ron English, Kenny Scharf and Robbie Conal (guest voicing as themselves), and to Bart's surprise, they invite him to exhibit his satirical artwork in his very own gallery show. Meanwhile, a hip, new health food superstore opens in Springfield that threatens to put Apu and the Kwik-E-Mart out of business.