Stan is complaining that he has to go to the meteor shower party with his parents. Upon arrival he is led to the basement and stuck in the "Kid's Room". The only kids there to Stan's horror are the three "Melvins" from school, Pip, Butters, and Dougie. Stan is freaked out at having to spend the night with the geeks.
Upstairs, Mr. Mackey shows Randy, Sharon, Gerald and Sheila his newly installed hot tub. Sharon and Sheila say they won't get in since they have nothing to wear. Randy and Gerald immediately jump in.
In the basement, Pip, Butters, and Dougie have finished playing an English game that Pip has introduced since he is English. Stan refuses to participate in their games and the others find women's clothing and decide to play Charlie's Angels. Stan is given the role of Bosley. In order to go upstairs, he gives them the task of finding a way out the basement, which they do.
In the hot tub, Randy and Gerald ask each other about what they'll do at the party. They choose to have a night of experimentation while Gerald explains he is smoking a cigar because he never has before. Randy asks Gerald if he'd ever had a gay fantasy and Gerald explains that he has always thought of watching another guy masturbate. The fantasy then becomes a reality.
Upstairs, Stan has the others find him some cookies and a TV in order to fulfill their next mission.
Outside, the ATF have arrived after suspecting the party to be some kind of religious cult that will commit suicide upon the beginning of the meteor shower.
Stan turns on the TV and discovers the ATF are outside and that they are planning to destroy the building in order to stop the cult. The boys embark on their biggest mission: to stop the ATF and prove it's a normal party.
Downstairs, Randy is having an extreme problem with having watched Gerald masturbate. Everywhere he goes he thinks people are talking about it. Gerald seems to be more "emotional" and this leads to Randy shouting out what he did. All the men admit that they have too and it doesn't make you gay.
Butters tries to explain to the parents about the ATF but they are too drunk to notice. They then make a mock news report to explain what's going on in the house with the help of Dougie. They need to take the tape downstairs but cannot go out the front door since they will be shot at as they were before. Pip uses his archery skills to shoot a plunger onto Officer Barbrady's head and Butters slides down to give them the news report.
The ATF have tried everything, from playing extremely loud Cher with gigantic speakers to using police negotiations. Then it's planned to use a missile launcher to destroy the entire house. Basically, it's a cartoon replication of the Waco Federal (FBI, BATF) killings. The newsman asked the ATF if they had any proof, but the ATF leader tells him that they know what their doing. The newsman reminded the ATF that the last time they did this without any proof, they ended up killing innocent people. The newsman at the event soon shows the news tape and explains it's just a party.
The ATF accidentally launch the missile and it destroys three other houses. The ATF leader covers by explaining that it was just a simulation and they all leave.
Stan explains to the others that he shouldn't ridicule them and that they're actually okay people. Kyle shows up with Ike from Jew Scouts suddenly and Stan reverts to his old ways of mocking the "Melvins".