Butters is fired as the boys fourth friend and they start a search for a new one.
Meanwhile Proffessor Chaos (butters) and General Disarray plan to destroy the world through various means.
The reality show like contest for the fourth friend is downright hilarious and has a fine conclusion. I really like this episode and it places among my favorites, introducing Proffessor Chaos who is used throughout the series. If you don't want spoilers read no further.
The boys end up choosing Tweek. I really like Tweek and how he plays out in the next few episodes, unfortunately they dump him with no real explanation before he really becomes an integral part of the story. I'm glad they brought back Kenny, but I wonder what South Park would be like if he had stayed dead and Tweek had become the permanent fourth friend.