During a trip to the State Fair, Homer and Bart save a diving horse named Duncan. To help pay for the horse's food and care, Homer tries to train Duncan to be a field goal kicker, but NFL regulations specifically ban the use of horses in professional football. As Homer curses the NFL and their draconian rulebook, Bart comes up with the idea of turning Duncan into a racehorse. With a pajama-clad Bart as his jockey, Duncan loses his first race. Bart and Homer are the laughingstocks of the racing community, but after giving Duncan a Rodman-esque makeover as a bad-boy rebel renamed Furious D, they take the racing world by storm. Furious D intimidates all his competitors with his dyed hair and nose ring. Miraculously, Furious D and Bart become champions. After a race, Homer is ambushed by crazed, singing jockeys who reveal themselves to be magical elves who live in an underground lair. The jockeys tell Homer that if Bart doesn't lose the big Springfield Derby, they'll eat his brains. Terrified, Homer tries to convince Bart to throw the race. Bart refuses and he and Furious D go on to win it all. But the victory is brief as the murderous elves pursue Homer, Bart and Duncan as they flee the racetrack and try to make it home. It's up to Marge and her trusty garden hose to stop the elves before they can dine on what's left of Homer's brains. Homer throws out the elves with the trash and the family says goodbye to Duncan, who gets put out to stud.