To the amazement of all the other boys, Kenny has a new girlfriend, Tammy, who is in the fifth grade. Butters hears a rumor that Tammy is a slut because she gave Dave Darsky, another male student a "B.J.", aka a blowjob. in a T.G.I. Friday's parking lot, and Stan, Kyle, and Cartman, hoping to spare Kenny's feelings, decide to warn him. To his friends' bewilderment, however, Kenny is ecstatic, even after Cartman explains his belief that an American woman's mouth is the dirtiest thing on Earth. Kenny invites Tammy to go with him to T.G.I. Friday's after school, at which point she confesses that the rumor about her is true, but explains that the only reason she did it was because she became aroused after watching the Jonas Brothers perform. Consequently, Kenny takes Tammy to a Jonas Brothers concert, with his friends disgusted by his intent. At the concert, many girls rave about the famous trio, while Kenny seems to be having the worst time of his life.
After the concert, Tammy and several other girls are invited backstage, where they think the Jonas Brothers want to have sex with them. Instead, the Jonas Brothers convince them to wear purity rings as a pledge to abstinence and tell them to get all of their friends to start wearing them as well. To make his girlfriend happy, Kenny reluctantly begins wearing a purity ring. As Kenny becomes dull as a result and ceases to spend time with his friends, it is revealed that the Jonas Brothers are being forced to wear and promote purity rings by their boss, a greedy, sadistic, foul-mouthed version of Mickey Mouse, who berates and beats them when they complain that the rings are overshadowing their music and projecting the wrong message. Mickey explains that the rings allow them to give sex to young girls while giving the appearance of innocence and purity. Concerned for their friend, Stan, Kyle, and Cartman attempt to confront the Jonas Brothers at a televised appearance in Denver, but Mickey, believing that the boys have been hired by either DreamWorks or Michael Eisner to sabotage Disney, tranquilizes them and takes them prisoner.
When the boys regain consciousness, they are backstage at a Jonas Brothers concert, where Mickey at first interrogates them, then threatens to kill them with a chainsaw. As Mickey once again rants about his true intentions, insulting the Jonas Brothers' fans and Christians, Kyle and Cartman stealthily turn on the microphone and shortly after raise the curtain, and Mickey's rant is heard by both the concert-goers and the national television audience. The crowd turns on Mickey and the Jonas Brothers leave the stage in a huff. Enraged by the crowd's boos, Mickey grows to gigantic proportions and begins breathing fire and destroying Denver. It's unknown what became of him after this, as the news reporter states that Mickey merely returns to Valhalla to slumber and feed. Tammy and Kenny remove their purity rings, and Tammy suggests they go to T.G.I. Friday's, presumably so she can perform oral sex on him. Afterward, Kenny contracts syphilis and dies (for the first time since Season Eleven), proving Cartman's warning about American women's mouths correct.