Will and Idina Menzel receive confirmation that their choirs will be competing against each other in Sectionals and, as they're worried the children will declare "World War Glee" upon each other as a result, the two concoct a joint assignment in an attempt to channel the kiddies' roiling negative energies into something a bit more positive, because Will and Idina Menzel are actually filthy New Age hippies. Thus, they decide upon this episode's titular "mash-off," which tasks New Directions and The Troubletones with offering their best respective medley performances in order to win... well, nothing, really, but that's the primary plotline for this evening's installment, so there you go.

Frankenteen and Santana Lopez instantly start butting heads over the whole thing for reasons that remain unclear to me at this point and, after they try and fail to settle things with a entertainingly vicious game of dodgeball between the rival clubs, Finn maliciously outs Santana in the middle of a crowded high school hallway. Things immediately go from bad to worse for everybody's favorite bitchy cheerleader when one of Sue's rivals for that vacant Congressional seat gets word of the outing from his gossipy niece and proceeds to make Santana's supposed sexual orientation the centerpiece of his latest attack ad. Santana somehow manages to keep her head up at first, but when she spots Finn whispering something that may or may not be appropriate into a giggling Rachel's ear, she loses her shit in a most awesomely spectacular way and slaps the smug clean off Frankenteen's face.

In other news, Puck is still romancing Idina, but it's okay, because he's eighteen; Sue Sylvester's own over-the-top attack ads mock Burt Hummel's baboon heart, among other things; Idina learns of Quinn's nefarious scheme to regain custody of Dismal Drizzle and forbids her from ever seeing the child again; Brittany promises to go topless every Tuesday if she wins the student council election; and St. Gay Of Lima spends the hour vacillating between martyrdom and priggery. You know, the usual.

Featuring Van Halen's "Hot For Teacher," as performed by Puck, with backup from Dreamboat Blaine, Gaylord Weiner, and Frankenteen; a medley of Lady Gaga's "Yoü And I" (yes, it has an umlaut in the title, and no, I can't believe how much I fucking hate little Steffie Germanotta for sticking it in there, thanks for asking) and a different, correctly spelled "You And I" from Crystal Gayle and Eddie Rabbitt, as performed by Mr. Schue and Idina Menzel; a disastrous combination of Pat Benatar's "Hit Me With Your Best Shot" and Blondie's "One Way Or Another," ruined despite Santana's best efforts on the Blondie part by the inept Frankenteen's butchering of the Benatar; a somewhat more successful blending of "You Make My Dreams Come True" and "I Can't Go For That" by Hall & Oates as performed by New Directions, with featured vocals from Frankenteen, The Leprechaun, Single-T Tina, and Quinn; and, finally, Adele's "Rumour Has It" paired with her "Someone Like You," as performed by the divas of Idina Menzel's nurturing lady-choir, with solos from Mercedes and Santana Lopez.