The Simpson family attends a prison rodeo where Marge meets Jack Crowley, a convict whom she believes to have great artistic potential after becoming impressed with his work. She later teaches a class on being an artist to the prisoners and befriends Jack. With Marge's help, Jack is granted parole under her custody. Marge soon finds a mural-painting job at Springfield Elementary School for him. Jack paints a powerful, epic mural symbolizing school spirit with a warrior woman riding a puma, which the whole school likes, but Principal Skinner (who hates it) demands that he tone it down using Skinner's own childish idea of kittens in a fantasy land. Jack reluctantly gives into Skinner's wishes; however, upon its unveiling, the new mural is panned by everyone in town (even Ned Flanders). Skinner blames Jack and fires him.
Sometime later, the mural is set on fire by a mystery arsonist. There are no suspects; however, everyone in the school immediately assumes that Jack did it to get back at Skinner. While the police are out searching for Jack, Marge stumbles upon him hiding in the school playground. He swears to her that he did not start the fire, and Marge decides to believe him. She then distracts Skinner and Chief Wiggum so he can escape; however, instead, he immediately sets fire to Skinner's car as he did to the mural, and dances around it laughing maniacally. Jack is arrested, and Marge is furious that he lied to her. When Jack attempts to lie to her again—claiming this time that although he did burn the mural, he did not burn Skinner's car (despite the fact that she had just seen him do it)—she ends all her involvement with him forever, and on the way to jail, Jack and Wiggum make conversation.
Meanwhile, Homer begins suffering from a back injury and goes to see a chiropractor. However, he fails to follow the instructions given to him by the chiropractor and his suffering continues. Later, Homer accidentally falls backwards onto a round garbage can at home and discovers that it solved his back problems. He names the garbage can "Dr. Homer's Miracle Spine-o-Cylinder", and makes a business out of his discovery. It turns out to be a successful method of solving problems with pain, causing the chiropractic business to go in decline until the chiropractors in town denounce the method and destroy the garbage can at the Simpsons' home.