While having what he thinks is a lucky day Bart encounters a vicious dog that proceeds to chase him relentlessly, harassing him whenever he steps out of the Simpsons house. One day, he takes refuge in the garden of a house belonging to Buck McCoy, a former Western actor who was a big star in the early days of television. An experienced animal handler as well as an actor, Buck shows Bart a trick to calm the dog down, making it friendly towards him, and Bart begins to hero-worship Buck. Bart begins to spend a lot of time with Buck, who teaches him all manner of old cowboy skills, such as lasso tricks. The other kids of Springfield soon begin to emulate Barts new style, and the Western fad makes a comeback. Meanwhile, Homer grows jealous over Bart's hero worship of Buck, and tries to get Bart to idolize him instead. Buck befriends the rest of the family, and eventually talks about the end of his career, when the western shows were replaced by detective shows in the 60's. Lisa convinces Buck that he is due for a comeback
Bart manages to get Buck on the Krusty The Clown Show as part of his push towards a comeback, which is helped by Krusty being an old fan of his. The rehearsal goes great, with Buck's sharpshooting skills still being in peak condition, but when Krusty mentions how many viewers Buck will be performing for, Buck develops stagefright due to not having performed live in decades, and ends up getting drunk, accidentally shooting Krusty during a stunt, and revealing that he's an alcoholic, devastating Bart. Homer is at first elated, hoping to replace Buck as Barts hero, but seeing how much losing his faith in Buck has hurt his son, Homer instead decides to help Marge get Buck sobered up. Progress is slow, as Buck has little interest in cleaning himself up, and resists help from both Marge and Alcoholics Anonymous (who brands him with a cattle iron when he quits the program).
Meanwhile, Homer sees a news broadcast where the Springfield Bank is robbed by Snake Jailbird and several unnamed accomplices, using military-grade weaponry and body armor which the police is helpless against. Seeing an opportunity, Homer convinces Buck to become a hero by foiling the robbery. Though Buck first refuses, pointing out that he is an actor, not an actual gunfighter, the idea of restoring Barts faith in him is enough to get him aboard. Buck easily disarms the robbers with a pair of lasso, with the befuddled criminals being confused about how to counter the attack, and Bart once again sees Buck as a hero. Buck rides off into the sunset, asking Bart never to bother him again, and returns to his house, just as Bart is once again chased past by the vicious dog from the opening.