Follow That Egg! is one of the LGBT-themed episodes of South Park. In the episode, Mrs. Garrison tries reuniting with her ex-boyfriend Mr. Slave, but finds out that he is going to marry Big Gay Al after the governor of Colorado legalizes same-sex marriage in the state. Garrison, furious, goes to the governor and tells him that if same-sex couples get married, they will have the right to raise children, which she believes they are incapable of doing, and so decides to use a class project as a way to get the governor to change his mind.
Mrs. Garrison pairs off the kids in her class and assigns them to care for eggs as if they were babies as part of a lesson in parenting responsibility. Stan is worried he will get paired with his ex-girlfriend Wendy, whom he has not spoken to since their breakup. However, Wendy is assigned to Kyle while Stan is paired with Bebe. The assignments cause tension among the students, as Stan starts to suspect Kyle of having his eyes on Wendy while Bebe is angry at Stan's indifference to their egg.
Meanwhile, Mrs. Garrison is reminded of her ex-boyfriend Mr. Slave, who broke up with her after her sex change operation. Garrison attempts to take Mr. Slave back, only to learn that he is now in a relationship with Big Gay Al and that they are going to get married as soon as the governor of Colorado legalizes such unions. Mrs. Garrison, mad with jealousy, dedicates herself to doing whatever she can to prevent their union from being legalized.
Garrison makes plans for the final egg check in front of the governor's office, and, to make sure Stan and Kyle's egg is broken when they present it, hires an assassin named Jakartha to destroy the egg.
Kyle comes over to Stan's house and Stan tells him to just go be with Wendy, but Kyle reveals that he feared Stan's ability as a parent and so gave Stan a fake egg while he kept and saved the real one. Kyle also tells Stan that he had never had any interest in Wendy, since he just wanted an A on the project. The two boys reconcile and rush to the governor's office in a taxi, with Kyle calling Mrs. Garrison and telling her their egg is fine and that they are on their way. A horrified Garrison demands that Jakartha destroys the egg before it reaches the podium. Stan and Kyle rush through the crowd, narrowly avoiding Jakartha's attacks, and reach the podium weary and hurt. The governor inspects the egg and, upon seeing that it is undamaged, announces that same-sex marriage is now legal in Colorado.
The episode concludes with Mr. Slave and Big Gay Al marrying.