This week's episode of 'Glee' is called 'The Break-Up,' and it features the show's core couples dealing with serious relationship drama. The cast perform some of the most powerful break-up songs of the past two decades on the show.

Reports suggest that the four couples whose futures are in jeopardy — Finn and Rachel, Kurt and Blaine, Brittany and Santana, Will and Emma — will all join forces to sing Coldplay's somewhat depressing ballad 'The Scientist.' Finchel and Klaine team up on another tearjerker, No Doubt's 'Don't Speak.' Blaine and Finn, whose spontaneous road trip to New York City leads to tearful conversations with their significant others, duet on Duncan Sheik's 'Barely Breathing.'

Perhaps the most moving song of the episode is Blaine's solo performance of Katy Perry's 'Teenage Dream' on piano. That's the first song Blaine ever sang to Kurt, and now he fights through tears to sing it again, perhaps for the last time.

After all of the drama surrounding her relationship with Finn, Rachel ends up singing Demi Lovato's 'Give Your Heart a Break' with Brody. They turn the infectious pop tune into a piano ballad built around their harmonies, and they really let loose and wail near the end.

Meanwhile, one other happy song does manage to find its way into the episode. Santana serenades Brittany with Taylor Swift's 'Mine,' singing, "You are the best thing that's ever been mine."

Catch Season 4, Episode 4 of 'Glee' on Thursday, Oct. 4 at 9PM ET on FOX.

'The Break-Up' Song List:
-Blaine & Finn, 'Barely Breathing' (Duncan Sheik)
-Rachel & Brody, 'Give Your Heart a Break' (Demi Lovato)
-Blaine, 'Teenage Dream' (Katy Perry)
-Finn, Rachel, Kurt & Blaine, 'Don't Speak' (No Doubt)
-Santana, 'Mine' (Taylor Swift)
-Finn, Rachel, Will, Emma, Brittany, Santana, Kurt & Blaine, 'The Scientist' (Coldplay)

See a Promo of 'The Break-Up'