Stan, Cartman, and Kyle call Butters over and inform him that he is too lame to be their friend and is being fired. Distraught, Butters wanders home and laments at his bedroom window, recalling the many things he did for the boys, such as buying tampons for them and going on Maury Povich with balls on his chin for them. Having received enough abuse. Butters vows to turn to evil. He constructs a crude costume from aluminum foil, complete with a Magneto like helmet, dubs himself "Professor Chaos", and promises to wreak havoc on the unsuspecting populace, though not before his mother tells him to go to sleep.
The next day, Stan, Kyle, and Cartman hold a contest reminiscent of "The Bachelor" in order to choose a new friend to take Kenny's place. Many children show up, as well as Towelie, and also children who had only appeared in one episode, such as Loogie, Mark Cotswolds, and Damien Thorn from "The Tooth Fairy Tats 2000," "Hooked on Monkey Fonics", and "Damien". The contest also includes background characters, such as DogPoo Petuski, who complains "I've been around these guys for like, five years, and never got to say or do anything.". The boys explain the best way to determine the worthiness of all these potential friends is to spend time with them, and so they go to the amusement park.
Meanwhile, Butters, in his new Professor Chaos persona, marches ominously down the street, looking to perform evil deeds upon the people of South Park, and enters a Bennigan's restaurant. Professor Chaos sees that two soup orders are ready and placed on the counter. He picks them up and switches them around, and watches as they are taken to their respective customers. Upon receiving the orders, the two customers, who happen to be sitting in adjacent booths, inform the waitress that he has received the wrong order, and the situation is quickly resolved. Professor Chaos, standing at the restaurant's entrance, laughs menacingly. The entire restaurant becomes silent and stares. Professor Chaos informs everyone that he will continue to wreak havoc. He exits the restaurant and everyone else once again goes about their usual business. Walking down the street again, Professor Chaos laughs menacingly at a passing dog, enters his home, and evilly rumples the clothing in all the dressers.
Back at the boys' contest, it is announced that they have narrowed their choices down to ten potential friends, being Token Black, Clyde Donovan, Craig Tucker, Timmy Burch, Pip Pirrip, Jimmy Valmer, Jason, Towelie, Loogie (referred to as Luigi in this episode), and Tweek Tweak. Cartman tells those who didn't make the cut to "get the fudge out." The rest are disappointed, and Dougie O'Connell complains that the boys never even got a chance to know him.
The next day, at the Stotch residence, Butters comes downstairs, eager to see the aftermath of his evil. He asks his mom if she has heard about the switched soup incident at Bennigan's, to which she replies no. Intrigued, Butters enters his living room and asks his dad for the newspaper. Butters opens the paper to see if his dastardly deed has been reported in the news. To his dismay, there is no mention anywhere of Professor Chaos's evil. Butters concludes that the liberal media is covering up the events in order to prevent panic. For this, he decides to take his evil to the next level.
At school, Ms. Choksondik is preparing a lesson, and Stan, Kyle and Cartman are testing the potential friends' ability to help with cheating in school. Ms. Choksondik asks the class to look for the chalkboard eraser, which has been lost. As the students are searching the room, Butters grins evilly in his chair, thinking to himself how no one will find the eraser, as he has buried it in his backyard so all that is written will stay on the board, which makes Butters think the amount of arithmetic will make people's heads explode. Ms. Choksondik calls off the search and decides to use the back-up eraser in the desk drawer. Not to be deterred, Butters asks to go to the bathroom. After Butters leaves, Professor Chaos barges into the classroom, steals Ms. Choksondik's eraser, and flees. Moments later, Butters returns. When asked if he has seen a little boy in a costume running off, Butters cunningly replies that he has, and that he was pushed onto the floor by this strange boy.
Later that evening, Butters receives an anonymous note telling him to meet the sender at the South Park docks. Butters dons his Professor Chaos costume and sets off for the docks.
Meanwhile, Stan, Kyle, and Cartman have further narrowed their choices to six potential friends: Token, Timmy, Tweek, Pip, Towelie, and Jimmy. Cartman again tells the others to get the fudge out. Disgusted, Clyde complains that this kind of decision should not be made into a game, to which Cartman hurls more fudge-related insults.
At the docks, Professor Chaos searches for the one who sent him the note. Dougie reveals himself, tells Professor Chaos that he knows his secret identity, and requests permission to join him in his conquest for evil, explaining that he, too, is an outcast. Professor Chaos accepts and dubs Dougie "General Disarray".
The next day, Stan, Kyle, and Cartman hold a Swimsuit & Talent competition for the six potential friends. After the swimsuit, portion, the contestants perform their talents: Jimmy does a stuttering standup routine, Towelie attempts to play "Stairway to Heaven" on his guitar while stoned, and Token does a sort of hula dance, winning the competition.
The boys later take their potential friends to a baseball game. There, Cartman kicks Pip out of the contest for requesting tea and crumpets from the snack vendors. Everyone is surprised to see Professor Chaos appear on the Jumbotron screen. Professor Chaos, with his new partner in evil General Disarray, plan to flood the world: They turn on a garden hose and let it run on the lawn. The people in the stadium begin to panic, but soon decide to spend their last moments on Earth partying in their underwear.
Later that evening, Professor Chaos and General Disarray are excited that their plans for world destruction are coming to fruition, but are annoyed that the garden hose has so far only flooded about a quarter of the lawn. Meanwhile, the Stan, Kyle, and Cartman deliberate over who to choose as their new friend.
The next day, while Professor Chaos and General Disarray are waiting for their garden hose to flood the world, the Water Department arrives and shuts the hose off. With no other options, Professor Chaos decides to resort to his most dastardly plan yet.
Meanwhile, Stan, Kyle, and Cartman have chosen their new friend, and are preparing to announce it.
Professor Chaos and General Disarray arrive at the top of a hill with a box of aerosol cans, and they proceed to spray them into the air in order to deteriorate the Earth's ozone layer. An announcer cuts in with the questions: "Will Professor Chaos's latest plot succeed and be the final undoing of Earth? And which boy has been chosen to be the replacement for Kenny? And which of these six South Park residents was killed, and will never be seen again? The answer to those questions will be answered... right now: No. Tweak. Ms. Choksondik."