Some info and a short description of this South Park episode on South Park Zone:
This South Park episode pokes fun at the formulaic storyline of some South Park episodes which start with the boys getting themselves in trouble and inciting a controversy between the townsfolk and a national interest group while trying to avoid punishments, subsequently learning a lesson from this conflict.
The South Park town calls in Rob Reiner to combat the spread of smoking among children after the boys are caught doing so.
In the end Stan is relieved that it is all over and that he and his friends learned their lesson, but Kyle flatly disagrees with him in obvious disgust.
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(The complete plot for this South Park Episode)
The episodes starts with an anti-smoking campain at South Park Elementary, supported by a music group called Butt Out, which incorporates elements of dance and hip-hop into its routine, performs at South Park Elementary's gym. The boys are put off by the triteness and overly sentimental nature of the performance, and after the performers proclaim they can be "just like us", they go behind the school and smoke furiously while coughing. When their school counselor Mr. Mackey approaches, the boys discard their still-lit cigarettes into a nearby dumpster, which causes a fire that burns down the entire school. When the boys are brought before the principal and their parents, the adults are initially enraged and ashamed, not at the school burning down, but at the boys smoking (in fact, the school burning down is not even acknowledged by either the principal or the parents). They then convince themselves that the blame lies with the tobacco companies, whose advertising campaigns have influenced the children. The boys happily transfer the blame to avoid punishment, but Kyle recognizes the pattern of a South Park storyline and unsuccessfully tries to get his friends to avoid the coming calamity. The town summons celebrity spokesperson Rob Reiner to combat the spread of smoking among children in South Park. Despite the fact that Reiner is vehemently against smoking and willing to tell everyone how unhealthy it is, he is portrayed as extremely gluttonous and disrespectful to those who do not share his viewpoints, constantly eating junk food and taking pride on imposing his will on others. Cartman, however, comes to look up to Reiner precisely because of this.Reiner disguises himself and takes the boys on a tour of Big Tobacco's tobacco factory. The Vice-President teaches them the history of tobacco, and explains that as the dangers of smoking have been made known they placed warning labels on cigarettes so those who choose to smoke or not can make informed choices, which Kyle finds reasonable. Reiner reveals himself after snapping a picture of the boys, and throws one of the employees over the railing to the factory floor before fleeing. Reiner takes the boys back to his anti-smoking encampment and tells them he is going to introduce them to some really "decent and caring" people of his "Anti-Smoking" staff, who are shown to be pale, hunched-over and dressed in black. Reiner intends to Photoshop the photograph in order to falsely depict the executive giving cigarettes to the children. By now Kyle and Stan are disgusted with Reiner and his tactics, so when Reiner offers them the opportunity for them to appear in an anti-smoking TV commercial, they decline, but Cartman eagerly agrees.
Cartman appears in the commercial to claim he is dying of lung cancer from second-hand smoke, but discovers at the end of the shoot that Reiner and his group intend to kill him and claim it was from lung cancer. Cartman flees to his friends, who consider taking him back to the cigarette factory. Kyle again warns that this is following a formula, and will lead to a confrontation between the town and the factory where they will have to admit they lied about why they smoked and talk about what they have learned. However, the group goes to the factory anyway and the townspeople confront them with Reiner. The townspeople turn on Reiner when he tells them his plan, and as he attempts to explain it is okay Kyle goes into a speech (which he briefly breaks almost immediately to comment to Stan, "See? I knew it.") about people needing to take responsibility for their actions, and calls Reiner a fascist for imposing his will on others. Cartman stabs Reiner with a fork, causing his "goo" to leak out and killing him. The parents then ground the four as they know they smoked of their own will, and though Stan is relieved that the ordeal is over and the four have "learned their lesson", Kyle disappointingly replies "No we didn't dude. No we didn't."