"Lice Capades" is the third episode of Season Eleven, and the 156th overall episode of South Park. It aired on March 21, 2007.
The fourth grade class won’t be denied their rights as children to make fun of the unfortunate kid who has lice.
Confidentiality about who has head lice must be maintained so no child is embarrassed; so says the administration at South Park Elementary. When Garrison refuses to name names, Eric Cartman finds a way to detect who has the head cooties.
At the same time, a lice population faces an immediate threat coming from the outside world.
Everyone is called to the gymnasium for hair lice inspection. Clyde is informed he has lice, and has to visit a doctor who prescribes him a special shampoo.
In Clyde's head, there lives a civilization of lice. One of them, named Travis Mayfield, discovers a human doctor inspecting their world, and informs Vice President Greg that the outside world might be reacting to lice's activity, and that there should be a lice-wide evacuation. Travis is not taken seriously, by no one except his wife Kelly.
Later, it starts raining (Clyde showering), but Travis perceives the event as an omen and insists for Kelly and their daughter Hope to run. Some other lice notice a substance (special shampoo), and quickly find out it will kill them from continuous exposure. Soon, most of the population start to melt and disfigure due to the acid.
Travis, Kelly, and Hope flee to the "trees" (hair follicles) with the remaining lice. They survive the shampoo, until a large gust of wind (Clyde drying his hair), knocks many of them off towards the ground below. As the wind blows, Kelly's arm breaks and she falls to her death along with many others, leaving Travis screaming in agony, alone with Hope.
The next day, Cartman asks Ms. Garrison who had lice, but she will not say. Class ends, and the students suspect their classmates, prompting Cartman to discover a way to find out who it was.
Travis wakes up and meets the Vice President, and a handful of surviving lice, most of them badly disfigured and injured. While most of them decide to stay behind, Travis, Hope, an unnamed female louse, and the Vice President start to travel into "The Forbidden Zone" (Clyde's face) in hope that from there they can travel in to an another world. The Vice President loads his Glock 17 before following Travis and his crew.
Cartman invites the boys for a test (which doesn't actually work) that later suggests Kenny McCormick had the lice because he is poor. Kenny runs for his life out of the school.
At Clyde's house, the boys tell Clyde they're going to sock bath Kenny (washing him with wet soap and drying him off with dirty socks) and that he should come. Clyde says he'll come in a minute. As the boys leave he phones Ms. Garrison and tells her what's going to happen.
While Travis and the female louse share a romantic moment, the female louse is shot by the Vice President. The Vice President plans to repopulate their world and have lice like Travis out of their lives. Travis is soon shot in the knees upon entering "The Forbidden Zone" (the back of Clyde's neck). The Vice President shoots the ground, saying "If the world were conscious, it would feel this". Soon Clyde grabs him, and throws him onto the sidewalk, as Travis muttered a low, crying laugh, effectively disproving the Vice President's laugh.
At the park the boys prepare Kenny for the sock bath when Kyle Broflovski stops them and tells them it was him who had the lice. Stan Marsh is surprised since he thought he was the one. Then, even Cartman reveals he had lice and he was trying to frame Kenny. Ms. Garrison eventually arrives and reveals that everyone in the class had head lice and explains how quickly it spreads to people. Regardless, all the students (except for Clyde) give Kenny the sock bath anyway as a punishment for lying about his case of lice (although the whole thing was technically Cartman's fault in the first place).
As Travis lays dying a fly lifts him up and takes him to a new place where bigger red lice are, where they have lived in peace for "generations". They help Travis and Hope and welcome them to their land. As Travis celebrates their victory, it soon turns out the place is Angelina Jolie's pubic hair and the lice were crabs.