Cartman wants to race with the pros and he's ready to do whatever it takes to make it happen. He's afraid that no matter how hard he tries, he'll never reach the level of the other NASCAR drivers. Working with Butters as his pit crew chief, Cartman pulls out all the stops to compete in the race of his life - but Kenny will put his own life on the line to stop him from ruining NASCAR's reputation.
The episode begins with Cartman crying in front of his locker. When Stan and Kyle approach him, he explains that he is upset over the fact that Mr. Garrison assigned an essay about what the students want to be when they grow up, and he does not like to think about that subject. He then explains that it is his dream to become a NASCAR driver, and that he believes that this could never happen to people like him. Stan and Kyle, believing him to be talking about his excessive weight, try to comfort him. He reveals that he was in fact referring to the fact that he is not poor and stupid, as he believes all NASCAR fans and racers are, using Kenny for proof. The other boys, now disgusted at Cartman as he yet again reveals his usual prejudice, effectively convince him that he is, in fact, very poor and very stupid (trying to insult him back in the process).
Cartman takes their "encouragement" to heart and recruits Butters to be his pit boss, and sets out to become poorer and stupider than ever. He gives Butters all his money (which Butters spend on canned food and blankets, to a bunch of NASCAR fans (Kenny included) at the South Park Mall) and watches Charlie Sheen in Two and a Half Men upside down, and by chance sees a Vagisil commercial. One of the side effects of Vagisil is that it may cause temporary memory loss. Seizing the opportunity, Cartman eats many tubes of Vagisil at a pharmacy, claiming that it makes him "feel stupid".
On race day, Cartman manipulates his way onto the track by having Butters convince one of the racers (Dale Evans) that his wife was raped. The resulting catastrophic accident leaves 11 people dead and Cartman reconsidering his decision to be a racer, by crashing into a lake and sending him to the hospital. The doctor at the hospital tells Cartman that his accident was among the stupidest he'd ever seen, and Cartman is hopeful again to be stupid, much to the joy of Butters.
Kenny, meanwhile, has been reading NASCAR 2010, when he sees a newsflash that NASCAR fans probably are poor and stupid given Cartman's accident. He gets angry and storms round to Cartman's for the primary reason to yell at him. He discovers Cartman, to make himself "poorer", has been buying tons of sumptuous things in debt with no money down for two years so he would always be poor, causing Kenny and Cartman to angrily argue about being poor and NASCAR. The creator of Vagisil (Geoff Hamill) gives Cartman a new car because he promoted his product accidentally, much to Kenny's annoyance and/or chagrin.
Then the day of the race starts, after Cartman and Butters podcast on Vagisil and saying Obama gay as hell, Kenny is livid and wanting to put a stop to this, Cartman races again and is dumb and stupid as before. At the same time, Geoff, one of the announcers, frequently references his wife's odor. Kenny arrives and tries to smuggle in a sniper rifle, but this is confiscated by a security guard since this is what is making NASCAR look stupid, though he mentions they are also available in the gift shop. Cartman leads in the beginning (after eliminating many drivers and killing even more people), but Kenny jumps onto his car to try and stop him. Cartman throws him off by braking suddenly, and Kenny narrowly escapes being run over after two of the other drivers. Eventually, the Vagisil creator's wife, Patty Hamill, takes 6-time NASCAR Champion Jimmie Johnson's wrecked car and uses it to knock Cartman out, and promptly wins the race (being the only car Cartman hadn't smashed), much to Geoff's horror and/or frustration. In the end, Cartman thinks that he wasn't poor and stupid enough to be a NASCAR driver and accepts that he is too smart and rich for NASCAR. He gives a rare apology to Kenny before demanding Butters gives back his money, despite the fact he told Butters to spend all of the money in the first place, Cartman and Butters walk away arguing, while Kenny stares in complete confusion, ending the episode.