This week, Mr. Schuester assigns the Easy Listening genre for the glee club's assignment. The members of New Directions are not too excited by the idea and Kurt tells Mr. Schuester there's a Facebook group petitioning the glee club to perform Britney Spears at the homecoming assembly. Everyone is excited about the idea except for Brittany, who's name is actually Brittany S. Pierce and she feels like she's lived her live in Britney Spears' shadow. Will goes to discuss the idea with Emma and she believes that Britney would be a good topic for the glee club and tells will that he's too uptight. While they're talking, Emma's new boyfriend, Carl, pops in for a surprise visit. He complains that most of the students at McKinley High have poor dental hygiene and wants to talk to the school about having a seminar. Will offers to let him speak to the glee club in the hopes of getting into Emma's good graces.
Other members of the football team attack Finn and rip up his varsity jacket. They said that now that Finn is off the team he no longer deserves the jacket. Artie comes over to apologize to Finn for getting him kicked off the team and also saves Finn from getting in a fight with his old teammates. Back in the glee room, Carl has brought plaque tablets for the kids. Most of the students have great, clean teeth with the exception of a few - Brittany, Artie and Rachel. Carl suggests they come in to see him.
Brittany is the first to visit Carl and just as he puts her under general anesthesia for her abundant cavities, a Britney Spears song comes on the radio. As Brittany goes under, she begins a dream sequence where she is Britney Spears singing "I'm a Slave 4 U." Carl has Brittany return for another session since he could not fill all the cavities at once. Finn asks Rachel how she feels about his being kicked off the football team. Rachel is actually relieved that he's no longer on the team. He's hurt by her comments but she says she is just being honest with him. After Santana criticizes Rachel's outfit in passing, Finn doesn't defend Rachel and he says he agrees with Santana and he's just being honest.
Brittany returns to the dentist's office but this time Santana comes with her. Despite having perfect teeth, she wants to go under anesthesia and Carl agrees to give her a super strong bleaching. This time the pair have another Britney Spears fantasy, this time to Britney and Madonna's duet "Me Against the Music." The fantasy ends with Brittany talking to Britney Spears. Brittany returns to glee with a new found confidence and demands to have all future solos. Kurt defends her decision and urges Mr. Schuester to let them perform Britney Spears at the assembly. After Schue turns him down again, Kurt calls him uptight which in turn got him sent to the principal's office.
Will is the next to visit Dr. Carl. The two have a bro-to-bro talk about their feelings for Emma and Will agrees to back off unless Emma makes a move toward him. Carl then gives will some candy to help with his teeth grinding. Will passes by Rachel in the lobby of the dentist's office and asks if she needs him to stay and wait for her. Rachel insists she's fine -- she's been taking anti-anxiety pills and reading Britney Spears' unofficial biography to stay calm. After she goes under the anesthesia, she begins a "...Baby One More Time" fantasy. After coming to from the anesthesia, Rachel asks, "Is this real life?"
Rachel goes back to school in a Britney Spears inspired school-girl outfit - getting the attention of many students, including Jacob Ben Israel. Finn is uncomfortable with the attention she is getting. She tells him that they cannot control each other and she gives him her blessing to rejoin the football team.
Will tries to loosen up and buys a brand new car -- the same car as Carl and tries to impress Emma by taking her for a spin. Their joy ride is ended abruptly when Terri shows up at school. She asks him to to spend money on something he can't afford. After Emma leaves, Terri tells will that one day he'll wake up and return to the woman who loves him.
At glee, Santana tells Rachel she actually enjoys her new look. As practice is about to begin, Sue steps in to have a word with Will. She tells Will that she walked in on a naked Jacob Ben Israel in the library salivating over a video of Rachel in a school-girl outfit. She tells Will that that Britney Spears is a gateway drug for sexual deviance.
It's now Artie's turn to visit the dentist. As he goes under he talks to Britney Spears in a Cheerios uniform. Britney tells Tina that she was a fool for breaking up with Artie as he wheels off to the football field singing "Stronger." Back at the locker room, Artie approaches Finn for help in joining the football team once again. Finn turns him down but Coach Beiste overhears the conversation and puts both of them back on the team. Rachel confesses to Finn that she thinks their relationship will only work if they are both losers. She wants him to choose between their relationship and football. Finn tells her that she has nothing to worry about. At glee, Will has also changed his mind and allows the group to perform a Britney number at the homecoming assembly.
The assembly begins and New Directions performs a rousing rendition of "Toxic." Sue is enraged and pulls the fire alarm at the end of the performance. Quinn approaches Finn in the hallway with a proposition. Now that she's head cheerleader again and he's back on the football team, it only seems right that they get back together. Finn admits that while he may always have feelings for her, he's with Rachel now. Quinn walks off to Rachel, saying she did what Rachel asked but Finn really likes Rachel. At glee, Rachel performs a song from their original "adult contemporary" assignment and dedicates the song to Finn.