It's not what they think. The reason Kurt is so out of sorts is not just because of prom, which is coming in a week. It's the extra credit assignment that Mr. Schuester has given. Kurt had sat forward with anticipation, until he saw the words scrawled on the white board in red marker.

MOTHER'S DAY.

"The assignment - should you choose to accept it - is to perform a song about Mother's Day. You can choose to sing about your mother, or what Mother's Day means to you. This is not required, so if you're not comfortable with this theme, feel free to focus on prom music," Mr. Schuester says with a smile.

He probably thought he was being kind by allowing the theme to remain open, and optional, but the truth is, the existence of Mother's Day at all is like salt in an open wound for Kurt, who hasn't had a mother in ten years. He cuts his eyes around the room. He spots Rachel first, looking like a deer in the headlights, and Kurt understands.

Rachel just choked at her NYADA audition. She's still fragile. This is not what she needs. Kurt knows that it's in Rachel's DNA. She's incapable of passing up an opportunity to perform, even if it means opening up a painful wound.

Quinn makes a beeline for the door.

Kurt wonders if Mr. Schuester realizes what this is doing to them.

Over the next few days, Kurt endures Mercedes, Tina, Santana, Brittany, Finn, Sam, Mike and more of the glee club, thrilled about what they will sing to honor their moms. Every time Kurt thinks about the assignment, his heart feels heavy in his chest. This isn't fair, but he doesn't have the energy to tell Mr. Schuester to approach his lesson plans with a bit more sensitivity.

He falls into step beside Rachel - who hasn't sung a note since her audition that he's aware of - and lays a hand on her shoulder. "Any ideas for the glee extra credit?" he wonders, keeping it as innocuous as possible.

She shakes her head once. "Maybe we can stay after and talk about it…" she ventures. "I don't want to bring it up around my dads. They say it doesn't, but I know it hurts their feelings when I talk about anything relating to moms."

Kurt squeezes her shoulder. "I'll be here. Should I meet you in the auditorium or the classroom?"

"Auditorium," Rachel decides, surprising him. Kurt hadn't thought she would be up for auditorium singing since her audition.

"Okay," he answers.

However, by the time Kurt and Rachel arrive at the doors to the auditorium, it's obvious that they are too late. They can hear someone inside, playing a simple, gentle melody on piano. Rachel can't stand not knowing who it is, and opens the door to peer inside.

Quinn sits at the piano, with a sad, but determined expression. Kurt wonders how she managed to get up to the stage - how she moved the piano bench aside - and decides not to comment about it. He has watched Artie for years - knows that it is possible to adapt - if you're forced to.

They sit quietly and listen as Quinn's quiet voice fills the room. The lyrics hit Kurt right in the center of his chest. He hears Rachel catch her breath abruptly. They sit side by side, unable to tear their eyes away from Quinn. Every time she gets to the chorus, emotion overwhelms her, and she simply plays through it.

When she finishes, there is no applause, she says simply, "Puck wants to sing this…but I can't do the chorus without losing it." Quinn wipes a hand across her eyes.

Kurt eyes Rachel carefully. "Well we can't sing those verses with any authority, and I'm not a huge fan of country music…but if you'd let us…we'd love to help."

They practice for only an afternoon. Puck makes an appearance with his guitar and they go through the number a few times, before he begs off to clean pools. It doesn't matter, though. Because now, they have the perfect arrangement.

The next afternoon, Mr. Schuester almost doesn't call on them at all. He assumes that since they haven't performed yet, they won't be. Kurt is about to show him just how wrong he is. Blaine squeezes his hand before he gets up to join Rachel, Quinn and Puck at the front of the room.

Puck starts out on guitar, and sings the first two verses, singing the melody, while Quinn harmonizes. Their voices sound strange together, yet somehow, suited for each other. There is no doubt that they're emotional. Puck never quite raises his eyes from the floor, and Quinn never really looks at anyone. Kurt knows that she's picturing Beth. They lead into the chorus where Kurt and Rachel take over effortlessly. The words catching in his own throat, just as they had for Quinn.

The next two verses are harder than the first, Kurt knows. Still, he watches, impressed, as Quinn takes the melody and Puck the harmony. Kurt listens, blinking tears back, and taking Rachel's hand in his.

Rachel sings the final verse alone. It's fitting. About moving on and saying goodbye to her fathers. Kurt takes the chorus, and then, finally, they all sing together on the refrain.

Kurt excuses himself once the song is over, and he knows without looking, that Rachel is right on his heels. God, he misses his mom. It's no wonder the lyrics he chose were all about loss of life, of future, of everything he ever thought of as important. This hurts like a physical pain. He makes it out the door and sinks to his knees in the hall, just in time to feel Rachel embracing him from behind.

"I miss her," he chokes, reaching over one shoulder and touching Rachel's hand.

"I know," she manages.

And they stay like that until the doors open again. Until Kurt feels Quinn lay a hand on his back, and Puck stands nearby - his guitar slung over his back - guarding this sacred moment. He doesn't say a word about Kurt or Rachel's tears.

In fact, none of them says anything at all.

The End.

The song Kurt, Rachel, Quinn and Puck sang was "There Goes My Life" by Kenny Chesney.