just need to ask me
In a class presentation, Cartman delivers something that could be considered a hate speech, arguing that "Gingers"—people with red hair, freckles, and pale skin—are disgusting, 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 class 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.
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. Now all Ginger kids are treated as outcasts and forced to eat in the hallway rather than the cafeteria. The other three members of the gang agree that they really need to teach Cartman a lesson.
At night, Kenny, Kyle and Stan sneak into Cartman's room and use skin bleach to make his skin pale, dye his hair red and put Henna tattoos of freckles on his face (but first they make sure he is unconscious, which Kyle makes sure of by whacking him with a small club more times than needed, due to his abject hatred of Cartman). Cartman wakes up in the morning to discover that he now has the disease 'gingervitis' and has become a Ginger himself. The boys' lesson goes off with flying colors. Cartman is taken to the doctor, who turns out to be prejudiced himself and soon insults him, even suggesting that Mrs. Cartman have him put down, which she considers. 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.
Initially peaceful, Cartman's movement quickly becomes violent and Nazi-esque in tone, arguing that Gingers are a "great race," though when he tries to name a successful "ginger," the GSR are forced to simply declare themselves as being like "Ron Howard … and others." He and his organization start holding protests, including beating up a brunette who played Annie, for playing a redhead but not actually being one. Eventually, Cartman, using the sentiment that "The only way to fight hate … is with MORE hate!" convinces the Ginger kids to decide to kill all the town's non-gingers.
In the dead of night Stan, Kyle, and Kenny decide to sneak into Cartman's room and change him back to his original appearance. However, on their way over, 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.
All the non-gingers are taken to the Sunset Room at the Airport Hilton Hotel, complete with a lava pit and refreshment buffet. They are all imprisoned in cages and will be chosen for sacrifice one by one.
"Daywalker" Kyle is chosen as the first; by Cartman's twisted logic, a "half-ginger" is much worse than one with no such trait. However, he asks that before he dies, he say something private to Cartman. Kyle whispers in Cartman's ear that he is not in fact a "ginger". Now thinking only of self-preservation, he realizes that if his own cult were to learn of his true physical identity he too would die with every other non-"ginger kid" of the town. Cartman pretends to have had an epiphany that everyone should live in harmony and peace since Kyle's speech. As the non-gingers are freed, Kyle mutters to Cartman that he is a "manipulative ***hole" to which Cartman (for once) agrees. "Yes but I'm not going to die".