Some info and a short description of this South Park episode on South Park Zone:
South Park - Ginger Kids is the 136th episode (Season 9, episode 11) of Comedy Central's series South Park. It originally aired on November 9, 2005.
Stan and Kyle turn Cartman redheaded and pale after Cartman does a report on how dangerous redheaded children are, but the prank goes too far when Cartman leads his "army" to fight for their rights by any means necessary.
South Park Spoiler Alert!
(The complete plot for this South Park Episode)
In a class presentation, Cartman delivers something that could be considered a speech, arguing that "Gingers", the people with red hair, freckles, and pale skin, are inhuman, unable to survive in sunlight, and have no souls, all because of a condition called "Gingervitis". When Kyle points out that he too has red hair, Cartman says that there is a second kind of redheads, the "daywalkers", who have red hair but not pale skin and freckles, and concludes that "If you think that the Ginger problem is not a serious one, think again!" while he clicks through a clip, and stops on a picture of Carrot Top (Scott Thompson by his real name, who is an American comedian, known for his bright red hair, prop comedy, and self-deprecating humor).In Kyle's attempt to prove Cartman wrong, he decides to do a presentation countering Cartman's, arguing that being a "ginger kid" is an inheritable trait. To prove this, Kyle and Stan visit a family who have "Gingers" for children. To their shock, the parents of the Ginger kids, who each carry a recessive gene that has caused them to have Ginger kids, possess the same prejudice towards Ginger kids as Cartman. The father of the Ginger kids informs Kyle that marrying an Asian woman ensures that the recessive gene is not passed down, and mentions a friend who is marrying an Asian woman for that reason, a reference to series creator Trey Parker. When Kyle makes his presentation, Cartman stands up for his claims and uses Biblical references, alleging that Judas was a Ginger. As a result, Cartman's speech causes a new-found prejudice towards Ginger kids in the school. Because of Cartman's speach, all ginger kids are treated badly, as outcasts and forced to eat in the hallway rather than the cafeteria. Kenny, Kyle and Stan agree that they really need to teach Cartman a lesson. So, that night they break into Cartman's house and after subduing him (Kyle strikes him unconscious) they dye Cartman's hair red, bleach his skin a lighter hue, and give him henna freckles, to make him look ginger. Both he and his Mother are horrified by the transformation, and Cartman's own doctor suggests that they "put him down" rather than deal with him as a Ginger. Liane considers this, but ultimately decides not to because Cartman is standing right there with her.
At school, Cartman is laughed at by Butters, is discriminated against by the very people he himself inspired to despise Gingers, and is forced to join them in eating in the hallway despite his attempts to convince them that he is still who he was. In response to this, Cartman establishes a movement—the Ginger Separatist Movement—to promote the better aspects of being ginger. His movement in the begining is peacefull but soon becomes violent, as Cartman claims that the only way to fight hatred, is with more hatred. Their first act involves savagely beating a non-ginger actress for playing the ginger role of Annie Warbucks in the musical "Annie". Cartman's group continues to grow in size and Cartman himself begins to preach that gingers are, in fact, the "chosen race," and orders the eradication of all non-gingers from the Earth. Anyway after Cartman plays his role as a dictator,Stan, Kyle, and Kenny decide to sneak into Cartman's room and change him back to his original appearance.
However, on their way over to his house, Ginger kids start to creep out of seemingly nowhere and follow them. At first, though terrified, the boys try to ignore them. Kenny is suddenly snatched away, prompting Kyle and Stan to break into a run. Meanwhile, kids across the town are abducted from their homes by the Ginger kids. Eventually, Stan and Kyle are the only ones left. They lock themselves in a barn for protection but the Ginger kids break in and overwhelm the two boys.
Following Cartman's orders, the gingers abduct as many of South Park's children as they can, including Stan, Kyle and Kenny, after which they bring them to their meeting place the Sunset Room at the Airport Hilton. The Hilton, in order to appease the group, sets up massive lava pit in the center of the Sunset Room, in which the Gingers ritualistically murder them. Kyle as a "Daywalker" is chosen as the first to die, but before the gingers throw him into the lava, he whispers to Cartman that he is not really a ginger, but instead was made up to look like one, by Stan, Kyle and Kenny. Cartman is shocked but the news, and quickly realizes that if his followers were to discover that he was not really a ginger, he would share the fate of the other kids. He quickly tells his followers that he has suddenly had an epiphany, and now realizes that everybody has to get along or else be as bad as the people who persecuted them. The gingers are initially suspicious of Cartman's change of opinion, but Cartman appeases them by singing "Hands in Hand". The gingers begin to free the other children, all of who join in on singing about how they should live together in peace. Meanwhile Kyle mutters to Cartman that he is manipulative, to which Cartman concedes is true (for once), but doesn't care because he will now not die - "Yes but I'm not going to die".