Cartman convinces the boys to toilet paper their art teacher's house as revenge for keeping them after school. After the fact, Kyle is overwhelmed with guilt and on the verge of confessing his part in the prank. Officer Barbrady is hot on the perpetrators' trail, while Cartman contemplates killing Kyle so he doesn't rat them out.
The boys have to stay after school for building an erect penis out of clay in art class. Annoyed about their punishment, they take revenge by toilet papering the art teacher Mrs. Streibel's house during the night. Kyle is horrified to discover that Mrs. Streibel has kids. He regrets their actions and has nightmares about their misdeed, and the Streibel family. The next day, the boys are called to the counselor's office. Frightened that they may be interrogated about what happened to the Streibel family, Cartman comes up with a bogus alibi: "Last night, all four of us were at the bowling alley until about 7:30, at which time we noticed Ally Sheedy, the Goth chick from the Breakfast Club, was bowling in the lane next to us, and we asked her for her autograph, but she didn't have a pen, so we followed her out to her car, but on the way we were accosted by five Scientologists who wanted to give us all personality tests, which were administered at the Scientology Center in Denver until 10:45, at which time we accidentally boarded the wrong bus home and ended up in Rancho de Burritos Rojos, south of Castle Rock, and finally got a ride home with a man who was missing his left index finger, named Gary Bushwell, arriving home around 11:46." Kyle is confused on the details of the story, and Cartman grows concerned that Kyle might confess.
Meanwhile, Officer Barbrady investigates the crime, but is unable to come up with any solid clues. He seeks help from Josh, a convicted toilet paperer, who is currently serving a sentence in Park County Juvenile Hall for toilet papering over 600 houses in less than a year. After several sessions with Josh, in which Josh applies psychological pressure to Barbrady, he comes a little closer to solving the case. The four boys are also interrogated.
Cartman decides to eliminate the risk of Kyle confessing by taking him out late at night on a boat in Stark's Pond to kill him with a wiffle bat.
Meanwhile, Barbrady forces a confession out of Butters, injecting him with sodium pentothal as a truth serum; but his parents ground him for lying and confessing to a crime he didn't commit. After seeing Butters get in trouble for their actions, Kyle is finally able to convince Stan and Kenny that they should confess. Stan tells Cartman that if he has any thread of a conscience, which as it turns out he doesn't, he'll do the same.
The next morning, Barbrady brings Josh along with him to Principal Victoria's office, but she insists that the true toilet paperer has already confessed, referring to Butters. Stan, Kyle, and Kenny rush into the office, only to find out that Cartman had already confessed to get a less harmful punishment; making the other boys look bad. Each of them received two weeks of detention, while Cartman got only one week for "being brave", although as far as he is concerned, one week of detention is still a terrible price to pay. Meanwhile, Josh manages to trick the police, and flee. Later, he calls Officer Barbrady to tell him there's something he must do. The final scene shows him approaching the White House with toilet paper as sinister music plays in the background.