So, that was kind of a hot mess of interlocking storylines. Rather than try to deconstruct it all into some semblance of order, let's just take it couple-by-couple, shall we?
Sue and Will. Okay, they're not a couple, except in some very disturbing fanfic. Will's only role in the episode is to learn that Figgins wants the Glee Club to provide the music for prom, and to convey that message to the club. And Sue's only role is to supervise the prom.
Rachel and Jesse. Yeah, you read it right -- Jesse's back. He flunked out of the University of California -- Los Angeles (you may have heard of it -- it's in Los Angeles) and is back in Ohio. He seems to want to pursue something with Rachel, but she's not ready to trust him. So they decide to attend the prom as part of a group, along with...
Sam and Mercedes. She wants to feel like a princess at the prom. He's poor. They dance together. That's about it.
Quinn and Finn. They look really cute going to prom, but he can't keep his eyes off Rachel -- he's clearly filled with jealousy at the return of Jesse. When Rachel and Jesse start making out, Finn confronts him, they fight, and they're both ejected from the prom. And then Quinn loses her race for prom queen. Quinn blames Rachel, and gives her a mighty slap. And then Rachel forgives her and they make up.
Puck and Lauren. Puck's worried that being so nice to his girlfriend is ruining his cred as a bad boy, so he recruits Artie to spike the punch. And neither he nor Lauren win their race for prom king and queen.
Artie and Brit-Brit. He sings a song to get her to accept his invitation to the prom. She turns him down so that she can attend the prom and dance with other people's dates. Heartbroken, he agrees to spike the punch for Puck. Sue catches him and threatens him with torture if he doesn't rat on his accomplice, but she has to back off when he tells her he only spiked the punch with lemonade.
Santana and Karofsky. They ramp up their campaign by escorting Kurt everywhere to "protect" him from bullies. Karofsky is elected prom king, but Santana is not elected queen, which makes her sad.
Finally, Kurt and Blaine. Kurt invites Blaine to prom. Despite his own history of being beat up after his own prom, Blaine agrees to attend. Kurt is elected prom queen in a write-in landslide, and he takes that as a cruel, homophobic joke from the student body. But after crying about it, he decides to stick it to the haters by accepting the crown. Unfortunately, Karofsky won't dance with him. But Blaine steps in, and soon everyone is dancing ecstatically.
Featuring ABBA's "Dancing Queen," performed by Santana and Mercedes, Rebecca Black's "Friday," performed by Puck, Artie, and Sam, Black Kids' "I'm Not Gonna Teach Your Boyfriend How To Dance," performed by Blaine, Stevie Wonder's "Isn't She Lovely?," performed by Artie, Christina Perri's "Jar of Hearts," performed by Rachel, and Adele's "Rolling In The Deep," performed by Rachel and Jesse.
We start by diving into the least essential of the episode's storylines. Jewfro is waiting in a crowded hallway to get an on-camera interview with Puck about the race for prom royalty. I always wonder what Jewfro does with these videos. Are they for his website? The school's television station? His own masturbatory video collection? Who knows. In any case, his ambush of Puck (whom Jewfro insists on calling "Noah") is designed to do three things. First, let us know that prom is six days away. Second, let us know that Quinn and Finn have a ten-point lead over Puck and Lauren Tuna in the prom royalty election (with Santana and Karofsky following right behind in third place). Third, raise the idea in Puck's mind that by being so nice and supportive to his girlfriend, he's giving everyone the impression that he's been neutered. Puck threatens violence against Jewfro for raising the last point (which Jewfro did by asking if Lauren has possession of Puck's balls), but Jewfro has gotten a bit braver in recent weeks: "I'm not scared, I've been hit by a girl before." And that ends the interview.
Maharishi's Palace of Plot Contrivance. He's called in Sue and Will to break some bad news to the two of them. Sue assumes that the news is that Will is leaving McKinley due to her devious plan from last episode. As a going away gift, she hands him a spray bottle of "I Can't Believe It's Not Butter" so he "can keep that head merkin looking buttery fresh." The real bad news that Figgins has is that the band that he'd invited to perform at prom has cancelled. That band? Air Supply. But Figgins has decided to fall back on his second favorite musical group, the New Directions. Sue, as prom coordinator, is incensed at the idea. She thinks that the horrific screeching of the Glee Club will just increase the likelihood that some kid will try to spike the punch, which is served in the very punchbowl in which Sue's grandmother drowned herself. Will is also not that thrilled, because the kids need to practice for Nationals. But Figgins won't take no for an answer. On the plus side, he's offering the Glee Club the entire $400 he was planning on paying Air Supply, to use towards the costs of their trip to Nationals. Sue, recognizing that she's beat, whips out the list of her least favorite New Directions performances (which she keeps on her at all times) in order to insist that the songs not be performed at the prom. Number one on her list? "Run Joey Run."