"...in order to get back at 'Homer', Bart goes undercover as a graffiti street artist and plasters Homer's unflattering image all over Springfield.
"Then 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).
"To Bart's surprise, they invite him to exhibit his artwork in his very own gallery show.