The episode begins with Brittany’s interview at MIT. Brittany has a 0.2 GPA but a near perfect SAT score. They guys from MIT wanted to personally see if she was MIT material and that is why they had her take an arithmetic test, which proved that she lacked understanding about basic arithmetic. She scored a zero. She ended up using crayons to mark her answers on the test paper. However, the guys are interested in the numbers she scribbled at the back of her test paper. They tell her that when they read the numbers left to right, they get a prime number. When the numbers are read right to left, they get the Avogadro’s constant and if they read it anti-clockwise, they get the Planck’s constant.
They tell her that she could be one of the most brilliant minds since Einstein and they will call these numbers the “Brittany code”, which would be a scientific breakthrough in quantum physics in the 21st century. They tell her that they have an unusual proposition for her. At McKinley, Ryder is still talking to Katie, but she doesn’t reveal her true identity. Ryder is angry. Will tells the group that the Nuntouchables have gotten disqualified so McKinley High will be hosting the Regionals in their auditorium. He also tells them that they will be competing against an all boys team, and their lead vocalist is extremely talented. Will tells the team to take a moment and applaud for Rachael, who is auditioning for her final callback for Funny Girl. Rachel sings “To Love You More” by Celine Dion for the audition.
At McKinley, Blaine tells Sam that he wants to propose to Kurt for marriage. Sam tells him that he is too young to get married. Blaine tells him that he has decided to go through with his decision, and wants Sam to be his best man. In the choir room, Will decides on the final list: “I Love It” by Icona Pop, “Hall Of Fame” by Script, and Marley’s original “All or Nothing”. Brittany arrives and tells the group that she wants to sing solo because she feels nobody compares with her mega star power. She also breaks up with Sam through a text, despite him standing right in front of her. Everyone is surprised. Brittany then goes to meet Roz and gives her 95 reasons as to why she is quitting cheerios. She also sets her uniform on fire. In the choir room, Will tries to prepare the group for the competition when Ryder tells them that he will not perform until Catfish reveals her identity.
Ryder tells them that he has told Catfish a lot about him and he cannot take it anymore. All this has gone too far. Marley tells him that she is Catfish. Ryder doesn’t believe that. Jake tells him that it all started as a joke but then it got out of hand. Ryder thinks that Jake is trying to defend Marley’s actions. He walks out of the room. Later, Sue and Will want to talk to Brittany. Brittany tells them that she will talk to them, but only on her show, ’Fondue for Two’. Brittany asks Will if he is planning to marry Emma. He says yes. Brittany tells Sue that she knows that Michael Bolton is the father of her child, Robyn. She produces proof. Sue admits that Michael Bolton is Robyn’s father. Will is shocked. Blaine takes Tina to buy an engagement ring for Kurt.
The salesperson, who is also gay, asks Blaine if Kurt is his soul mate. Blaine says yes. She tells him that she has been with her partner, Liz, for a very long time. She asks Blaine if there is someone (gay) who could advise him. She wants him to see what’s really possible. Sam calls Santana and tells her about Brittany. He knows that Santana doesn’t like him, but he says that he needs her help. At Breadsticks, Blaine and Kurt meet the salesperson, Jan and her partner, Liz. They have been together for thirty years. Kurt tells them that there aren’t too many gay role models to look up to. Jan proposes to Liz for marriage. Everyone present at the restaurant applauds for them. Marley tries to convince Ryder to compete in the Regionals. Ryder wants to know why she did it. Unique arrives and tells Ryder that she's Catfish, not Marley. She knows that she is not Ryder’s ideal beauty.
Unique thanks Marley for covering up for her, but it isn’t necessary anymore. Ryder tells Unique that they don’t have anything between them. He tells her that he is not going to punch her in the face, but he is not going to talk to her ever again. Santana is back on Fondue for Two. Santana tells Brittany that she is not here for the show. She tells Brittany that she came here to talk to her. Santana tells Brittany that she has been acting weird and this is not her. Brittany tells Santana that what she is about to tell her, will change everything. Next, it is Regionals. Emma joins Will in the audience. Santana is also present. Santana sees that Emma is wearing white and taunts Emma that she shouldn’t be wearing white because white makes Emma nervous. The competition begins with the Hoosierdaddies singing “Clarity” and “Wings”.
Will goes to check on his students. Ryder arrives and tells Will that he is officially leaving Glee club after the Regionals. Brittany arrives and reveals to her friends that she got an early acceptance at MIT and they want her to leave immediately. That is why she had that meltdown. She tells them that all her life people told her that she is stupid and she started believing them. She says that everything changed when she walked into Glee club, and she started believing in herself. She is in tears and tells them that she is going to miss everyone. She hugs Sam and tells him that she loves him and will miss him the most. She then hugs Santana, but there are no words for their relationship. It is show-time. They begin with “Hall Of Fame”. They then sing “I Love It”. Their performance ends with Marley and Blaine singing Marley’s song, “All or Nothing”.
The New Directions win Regionals. Will and the students are ecstatic. Unique and Ryder share a hug. Will tells his students that nothing can stop them from winning Nationals. Emma arrives in the choir room with a priest. She tells Will that she cannot handle the pressure of a big wedding. She tells him that she wants an intimate ceremony, surrounded by the people they love. The students are surprised and happy. Will hasn’t prepared his vows. Emma tells Will that he makes her feel clean and whole again. She tells him that they are just meant to be. She says that she loves him. Will also tells Emma that she is his true love. He wants to quickly skip to the “I Do” part. They are now husband and wife. Everyone is happy. It is seen that Blaine is still holding the ring he bought for Kurt, and he looks unsure about his next move. The season ends.