A/N: After they start dating in secret, before the Troubletones split and before Santana's outing. Yes, Rachel is in this. Never fear, it's Brittana to the core.

FRONT ROW, BABY

It took Rachel a week of Maria/Anita West Side Story rehearsals before she stopped flinching every time Santana made a sudden movement, and another two before she stopped anticipating vitriol every time Santana's mouth opened for something other than song.

It was an unfamiliar place to be in; Rachel was accustomed to being a target, with Santana the expert markswoman. Rachel didn't know how to re-write the story of their past hostilities into … whatever this tentative relationship was they had apparently struck up, and Santana wasn't helping her to define it. At all.

She wondered if Brittany, present at every rehearsal, stretched out in the front row with a smile (and sometimes Junior Mints), had anything to do with it. Probably. But that was a question Rachel didn't dare ask, and anyway, the warm crinkle around Santana's eyes every time she smiled past the footlights into the darkness pretty much answered it for her.

Whatever the reason, Rachel found that she and Santana were increasingly having … conversations. About things.

Like musicals. Or history class. Or why Americanos were better if you put half-and-half in them. Santana taught her how to say '¿Cuál camino a Broadway, por favor' without a hint of mocking, and Rachel showed Santana a breathing trick that helped her smash the high C-sharp in A Boy Like That. Santana accepted the lesson with good grace, later admitting that it had totally helped her upper register.

Once they spent twenty minutes talking about Billie Holiday; Santana rattled off a smoky, acapella adaptation of God Bless The Child – the live recording, not the studio version - that made Rachel's jaw drop and Brittany applaud wildly.

The weeks passed, and they settled into a comfortable rhythm. Santana had two hours of Cheerios practice immediately after school. The rest of the cast would rehearse then, and only Rachel would stay to meet Santana (and Brittany, in the front row), at five. Every now and again Artie would hang back to give notes, but for the most part, the three girls were left to their own devices.

Rachel never asked about Brittany. Santana never told.

MONDAY

"I've been thinking," Rachel said, eyeing her companion speculatively across the piano, "that we should do a proper duet together." Santana didn't respond. "For Glee," Rachel clarified.

Santana didn't look up from her sheet music. "Pfft."

Rachel's lower lip drooped a little. "Pfft?"

Santana folded the West Side Story songbook on her lap, leaned back, crossed her legs and tilted her head in a way that Rachel knew all-too-well meant a Lopez monologue was in the offing.

"Okay, Barbra. One, when you say 'duet', what you really mean is a sickly power ballad where you Liza Minnelli all the major stuff with your dewy cow eyes glued on Fetusface, and I gets to harmonise occasionally from five steps behind you. Two, our voices are completely different. Three…"

That's as far as she got before Rachel interrupted her. "Our voices are completely compatible, Santana! You may not have my range, but…"

Santana raised a mildly threatening finger. "Watch it, shortstack."

Rachel wilted a little, but rallied. "But you do have a texture and a tonal depth that I don't have, and never will."

Santana eyed her warily.

"It's the kind of thing that can't be taught or faked," Rachel continued, earnestly.

In the front row, Brittany beamed proudly and chewed on a Junior Mint.

"Listen." Rachel cleared her throat and sang, Well sometimes I go out by myself / and I look across the water / And I think of all the things, what you're doing / And in my head I paint a picture...

"Stop the violence," floated dimly from the front row, and Santana laughed. Her laughter used to seem like it was pulled from her with great reluctance. But not lately.

"See?" Rachel said.

"You can't do Winehouse," Santana said, a smile beginning, her hands on her hips.

"I can't do Winehouse," Rachel agreed, sadly.

"You totally can't do Winehouse."

"Okay, don't push it."

Santana grinned. "I mean, I cannot even believe how much you can't do Winehouse! Like, for God's sake, that sounded like a kitten singing! Or Aladdin!"

From the front row: "Ooh, do A Whole New World!"

"Okayokay!" Rachel snapped, a little more ruffled than she'd expected. "We've established that I can't do Winehouse. The point…" – here she raised a warning hand at Santana, who was grinning devilishly and about to speak – "is that we do complement each other."

Brittany popped into the footlights, draping herself over the edge of the stage, feet still stretched out to the front row seats. "No, you don't. Santana only compliments you when you're not here."

Santana's eyes narrowed. "Britt!"

"She thinks your voice is miraculous and that you're gonna be a huge star one day, but she says your head is already the size of a zeppelin so she'll never tell you that."

Santana looked desperately at Rachel, whose grateful, amazed smile could have shamed the sun. "Britt, I swear."

From the front row: "What's a zeppelin?"

TUESDAY

Rachel swung out onto the stage, and there Santana was perched atop the piano, in costume for the first time.

Rachel stopped, staring. "Oh my God, that colour looks incredible on you!"

"You know it," came from the front row.

Santana smiled. "Thanks, Berry." She hesitated for a brief second before adding, "You look all pretty and virginal yourself."

Rachel had the grace to blush, even as she heard Brittany chuckle. "Should we just get right into it?"

Later, on the third run-through, Rachel had lost herself in her verse.

I have a love and it's all that I have /Right or wrong, what else can I do?

Rachel paused and took a deep breath. Santana was sitting next to her, eyes downcast, sadness almost tangible on her skin. Rachel let the music keep playing. She felt Brittany's gaze on her from the front row.

Without thinking, Rachel reached out and covered both of Santana's hands with her own. Santana's head snapped up, and her hands jerked back like she'd been burned.

Rachel stood quickly. "I'm sorry. You looked…"

Santana flicked at something imaginary in the folds of her lap, and sighed in defeat. "Whatever. It's just a stupid song."

Rachel said nothing.

"It's just…" Santana continued, looking resolutely at the floor, "everybody tells her that it's wrong, but she can't help loving him anyway."

Rachel was silent, and heard Brittany's breath hitch in.

Santana shrugged. "I kinda get it."

"I know," Rachel said.

Santana's eyes darted quickly to Rachel's own, a mute plea in them. Please don't.

Rachel understood. "Should we start over?"

Santana nodded.

Later, exhausted, they were lying flat on their backs on the stage, Rachel chattering about her NYADA application. Santana was uncharacteristically silent, and not forthcoming when Rachel pressed her on her own college plans.

"You could do this, you know," Rachel told her. "I wouldn't say it to just anyone, but you're good enough to do this. You could apply to NYADA too."

Santana propped herself up on an elbow, assessing Rachel through one open eye. "You think?"

Rachel's lips quirked into a grin. "I do."

Santana lay back down. "Yeah, I dunno," she said, quietly. "I haven't really thought about college yet."

Rachel touched her hand. "Do you ever think about the future, Santana?"

Santana looked past her, into the darkness of the front row, and her face was unreadable. "Yeah. Yeah, I do."

WEDNESDAY

Rachel was offstage when Santana arrived, alone for once. She glanced out through the wings just in time to see a sad look cross Santana's face - before she realised Brittany was already waiting for her.

Santana dropped into the seat next to Brittany, and looked around quickly before pressing a sweet, swift kiss to Brittany's lips.

Even though Rachel had known – knew – that this must be what had been happening behind closed doors for a while – hell, for practically their whole lives, she was still vaguely shocked at the reality of it. She found herself scanning the auditorium on their behalf, checking the wings, making sure nobody else had seen. Her heart beat faster for them.

In the front row, Santana swung her legs up onto Brittany's lap, and Brittany folded them into her Cheerios jacket.

"Here you are."

"Here I am."

"Yeah, you are."

"Yeah, I am."

To Rachel it had the sound of a familiar private joke, one long-used. She smiled to herself.

Brittany started singing quietly: You look like a perfect fit / for a girl in need of a tourniquet.

Santana grinned and laced her fingers through Brittany's. "My front row girl. You're such a groupie."

Brittany leaned in and rested her forehead against Santana's. "I'll always be in the front row for you, Santana. Every time, every day, every night. Now. At college. After that, and after that, too."

Santana blinked and her eyes were suspiciously sparkly.

"Every song," Brittany promised. "Forever."

Rachel gave them a moment before clearing her throat noisily and stepping over-loudly towards the set. By the time she hit the stage, Santana was hopping up over the footlights with a smile Rachel had never seen before.

Later, when Santana spontaneously hugged her at the end of a run-through of America, Rachel felt like she'd been flooded with warmth. She returned the hug, Brittany clapping happily in the shadows.

THURSDAY

When Rachel and Santana announced they'd prepared a duet for Glee, Mr Schue's eyebrows weren't the only ones raised.

"Oh, park them, supersize," Santana snapped at Finn. "It's like two gigantic death's head moths are living on your face. Rach, pluck your sasquatch sometime, afores I covers him with flypaper and auction him off to a fetish group."

Quinn's shoulders shook with silent laughter in the back row, and Sugar and Mercedes both covered their grins. Tina turned to Mike and mouthed, "Rach?" Rachel, quietly thrilled, shrugged apologetically at Finn, who, she had to admit, could do with a tidy-up.

Their stripped-back Muse song was a smash hit, and their voices fit together perfectly, and Rachel smiled about that, and Santana got all the good lines.

I want to satisfy the undisclosed desires in your heart, Santana sang, to the front row, because on Thursday there was only one person in it.

FRIDAY (NIGHT)

Rachel froze in the back of the auditorium. She had come back to get her jacket, and wasn't expecting anybody else. It was past nine, after all, rehearsals had been over for an hour and she'd been in the choir room running through her dance steps away from Brittany's critical eye. But she heard rustling, and realised that there was someone onstage. It was dark except for a row of single, soft spotlights. The yellowing pools spilled dimly across the ground as Santana took centre stage.

Rachel knew she should either say something, or leave. She did neither.

Santana's voice was softer than Rachel had ever heard it. "I know I sang a duet with Rachel yesterday, Britt, but I really, really wish I'd been brave enough to sing one with you. Press play, okay?"

There was a brief pause, and then from the darkness of the front row, Brittany emerged, climbed up opposite Santana, and cocked her head, waiting. An acoustic guitar started, and for a reason Rachel didn't understand, Brittany gasped and pressed her hands to her heart.

Santana reached out and stroked her cheek. "I wanted it to be a surprise for you. Will you sing with me?"

Brittany's voice sounded tight, like she was trying to keep from crying. "You first."

"Okay."

Santana took a deep breath, and sang:

I would dial the numbers / Just to listen to your breath / And I would stand inside my hell / And hold the hand of death

Santana was lacing in and out of the spotlights, a flash of dark hair lit up, then swallowed again.

You don't know how far I'd go / To ease this precious ache / And you don't know how much I'd give / Or how much I can take

Brittany stretched out her hands towards Santana, smiling, and Santana fell silent.

Just to reach you, Brittany sang, and Santana's hands pressed into her stomach, like a reflex she couldn't control. Just to reach you / Oh... to reach you / Oh...

Rachel blinked. When had Brittany's voice gotten so wonderful?

They reached the chorus, and Santana swooped across to Brittany, taking both her hands. They sang and swayed together, voices blending seamlessly:

Come to my window / Crawl inside / Wait by the light of the moon / Come to my window / I'll be home soon.

Rachel was completely swept away. She sank into a chair and watched with a dreamy smile as the song continued, the girls weaving patterns across the stage, flitting from light to dark and back again.

When they reached the bridge, Santana took it alone, suddenly still, in the middle of a spotlight, an edge in her voice that wasn't there before:

I don't care what they think / I don't care what they say

Brittany crossed to Santana and stood quietly, watching her, unshed tears sparkling. Rachel felt her own eyes burn even as she watched Santana's close against the power of music. She groped for Brittany's hand. Her voice soared into the blackness, raw, and achingly beautiful.

What do they know about this love anywaaaaay?

Brittany's tears spilled over.

Santana turned and took Brittany's face in her hands, and the rest of the song played unheeded in the background as the two girls clung to each other in the spotlight and kissed with a fierceness that Rachel had never seen in anyone before, like they were drowning in it; Brittany's hands tangled in Santana's hair.

Rachel slipped her shoes off, quietly, and faded back up the stairs in silence until she reached the hallway. She couldn't un-see the song or the kiss, but she could make sure they never knew she'd been a witness to them.

Just as she exited, she heard Santana say, "I'll be ready to tell soon. I promise, Britt. I love you so much. I promise."

As she crossed the darkened parking lot to her car, Rachel felt a tightness in her chest she didn't quite recognise. It was almost like … almost like envy, curled into sadness, curled into ... hope.

THE END

A/N – The songs in this story were -

MON: Valerie, by Amy Winehouse. Obvs.

TUE: A Boy Like That, from West Side Story. Obvs.

WED: Save Me, by Aimee Mann.

THU: Undisclosed Desires, by Muse.

FRI: Come To My Window, by Melissa Etheridge. It's the song Brittany wanted Santana to sing with her in episode 2.04, Duets.