A/N: I've been bitten by the Grey's bug lately (what can I say - it's my newest fandom and I'm in love with so many different couples and characters that I don't know what to do with myself) and so I decided to try at writing Slexie. They're my second favorite couple at the moment, and when I got this idea I decided to write it. Please tell me if you like it!

Disclaimer: Even though I've been writing a lot of Grey's fanfics lately I am not Shonda Rhimes. I wish I was though, that would be awesome...

one.

She thinks about it every day. How she should've been on that plane. How that should've been her. She can't go a day without wondering how things could be different. What if she hadn't given up her spot on the plane at the last minute? What if she'd still gone? What if that had been her, crushed under the plane, left to die?

Lexie never knew the name of the resident who took her place, not until they announced her death anyway. Honestly, it makes her feel worse. Like she sent off some stranger to die in her place or something. And now everyday when she walks into work that name greets her, because when they bought the hospital Jackson had suggested they change the name to honor their fallen comrades.

Sometimes she still isn't used to it - that she's part-owner of the hospital. It feels so weird, being in charge. It had been Callie's idea, and at first they'd all thought it was crazy. But then, when they all saw the change going on in their beloved hospital, they'd realized what they had to do.

Now, she doesn't just do surgery, she sits at board meetings, has discussions and makes decisions. And every time they sit in a board meeting, she has to look across the table at the love she lost. She thinks it's her least favorite thing about those meetings. When they're over she practically sprints from the room, mumbles something about having a surgery. They all smile and nod.

Except for Mark. Mark knows.

Today, she rises from her seat as the meeting is dismissed, and when Meredith tries to stop her she makes up something about a craniotomy and walks out before they can all smile and nod today.

She's halfway down the hallway when she hears the footsteps behind her. They're too large to be her sister's. She sighs loudly and doesn't stop walking. "What do you want, Derek?" She snaps, because her brother-in-law is in neuro too, so he must be coming to talk to her about the imaginary craniotomy.

"Lexie."

Her blood runs cold. Her feet stop moving. Her fists clench. And when she turns around, Mark is only a few feet away, so close she could probably touch him if she wanted too. She feels her finger twitch, as if it's tempted.

She slaps her hand down without him noticing. "What...what is it, Mark?" She says. It comes out weak sounding, terrified. She hates herself for that. Why does she sound so scared? So...so frightened? She's Lexie freaking Grey. That's not her.

"Lexie," He begins, and she wants to tell him not to say her name, because when he does, she feels something in her stomach, fluttering.

Butterflies. That's it.

"I..." Mark says. "I know it's been hard for you, these last couple months. With the plane and everything. It's been hard for me too..."

"Mark," She says softly. "Where are you going with this?"

"Before the plane," He says. "You, you told me something. You said you loved me."

She looks down, feeling her face flush. How could she forget? She told him she still loved him and he never answered her back. How humiliating...

"I love you too."

Now, her head snaps up, meeting his eyes, her mouth forming a small 'o'. "I never stopped loving you Lexie. I was just too scared to tell you with everything that's happened - "

She doesn't realize she's leaning into kiss him until their lips collide. It feels so natural, like putting one foot in front of the other, like breathing, like returning home after years away.

The look he gives her is so full of love and awe. "I love you." He says. "This...this is meant to be."

The corners of Lexie's lips turn up into a smile. "Meant to be." She repeats, and the words feel just right in her mouth.

two.

Some days he doesn't know how he's still breathing.

And by some days, he means most. Most days he is plagued by the constant thought of 'why?'. Why is he still alive? Why is he still here when she - the woman he loved with all of his heart and soul, the woman who deserved a full and beautiful life a million times more than he did - had to die in that plane crash?

He feels empty, lost almost. He doesn't know why he's still here. He feels like he's lost all meaning in his life. Things that once brought him so much happiness do nothing for him. He's alone. On his worst days, he swears that if it wasn't for his daughter, he would've ended it a long time ago. Sometimes it feels like Sofia is the only reason he sticks around. She is the only thing that can truly numb his pain, if only for a moment.

He broke up with Julia a long time ago. It wasn't fair to her - to be stuck with a man who saw the ghost of his one true love wherever he turned. He can't go anywhere in the hospital without some memory of Lexie popping up into his mind. He imagines this is what being haunted feels like. And he'll never be able to love someone like how he loved her.

Sometimes it gets easier, like when he saves a patient in the OR, or when his daughter smiles at him and says 'Daddy'. For those brief, fleeting moments, he forgets his pain. For a moment, it's like he's his old self again. Then he turns, ready to share the good news with her, and remembers that he's alone. He's been alone for a long time now, and that will never change.

Sometimes he wonders why he didn't die. His injuries weren't too dire, though they did think for awhile that it wasn't looking good, and he can remember with painful clarity just how broken he was since that plane crash. He knows from experience a patient with a broken spirit is much harder to heal. It was like when she died, part of him died too. And they left the rest of him behind, to attempt to fill a void that will never be replaced.

Mark Sloan without Lexie Grey just doesn't make any sense to him. It never will.

three.

The dreams are what hurt the most.

She has them almost every night. She dreams of his face - back from the dead to personally haunt her, to yell and scream at her for why he had to have that seat on the plane instead of her. (Originally, it had been the one she'd been eyeing up, but then he'd sat there first. She hadn't thought much of it then - after all, what has the difference really? She'd thought nothing, but it turned out the difference between his seat and hers had been life and death.) In these dreams, he says he hates her, that if anyone deserved to live it was him, after all he had a girlfriend and a young daughter. She on the other hand barely saw her father anymore, and her half-sister was strong enough to survive without her. Those dreams make her wake up screaming.

Another dream she has is of when it happened, the scene playing over and over again in her head. The plane crushing his pelvis. Blood coming from his mouth. How she ran over, wrapped her fingers through his and just sobbed, because it couldn't end like this. She remembers how he professed his love for her with his last, dying breath, and then he was gone. Those dreams make her wake up crying.

But those aren't the worst. The worst dreams are the ones that make her think he's still with her. Dreams of his lips pressing softly against hers. Dreams of whispered I love you's and gentle caresses. Dreams of the two of them making love, their bodies fitting together like puzzle pieces, a perfect fit. Dreams of what they should have. Those dreams cause her to wake up feeling like nothing is wrong, only for her to realize the reality she is in when she opens her eyes. Those dreams stay with her all day, until she falls asleep again and is plagued with some other nightmare of Mark.

Life around her moves on, but she is still paralyzed by dreams of the love she lost. Sometimes, she wants to die too. Sometimes, she laughs or smiles or feels happiness again only to remember that she isn't supposed to.

She misses him with every fiber of her being. And it never goes away.

four.

The nurse on call greets him by name as he enters that specific wing of Seattle Grace Mercy West Hospital. He smiles briefly and faintly in response. She is a petite woman with a small waist and long hair, and maybe a few years ago he would've flirted with her. But today she does not get a second glance. He's a different man now.

When he opens the door to his destination, he finds her lying in bed, a surgical journal splayed open in her lap. When she sees him, her face lights up in that way it only does for him anymore. It's the face she used to have in the OR too, but just like he's a different man than he was a few years before, she's a different women.

"Hi," She greets him happily. He kisses her lightly on the lips, then slips over her, climbing next to her on the bed. His arm snakes around her waist.

"Hi," He says. He kisses her cheek. "That was from Sofia. She says she drew you a picture in day care today and she can't wait for you to see it."

A smile ghosts across her face at the mention of his daughter. "That's nice." She says, and she tries to hide the brief faltering of her expression. "So, while Sofia was coloring, what did you do today?"

He looks at her hesitantly before she assures him he can take it. He fills her in on the surgery he did with Derek today, the patients he saved. The whole time he watches her to see if anything changes.

When he finishes, she gets this look on her face, the emotion behind it something even he can't pinpoint. "That's nice." She says. "I wish I could..." She trails off, her breath catching. She looks down at her feet, limp and unmoving under the blanket, and remembers why she can't do surgery anymore, why he has to visit her in her hospital room on another failed physical therapy day and why Sofia draws her so many get well soon pictures. A cry escapes her throat.

He holds her tighter. "It's okay," He whispers. "I love you."

It's not okay. But he still loves her. He always will.

five.

She's cold. So cold. It doesn't matter in what position she curls up in, how she wraps the blanket, she's freezing.

Her lips taste like blood - she doesn't know if it's because of her injuries or because they're so chapped. I'd die for some lip balm right now. She thinks, and then she wishes she hadn't.

She closes her eyes, instead begging for sleep. Maybe if she sleeps the pain will go away. It's then that she finally feels warmth for the first time since they'd crashed. She tentatively opens her eyes, and it's Mark, slowly sinking into the spot next to him, wincing with everyone move, his arm wrapping around her torso.

"Hey," She says. The word barely passes her lips. She feels like she's half-asleep, like everything's fuzzy. Mark is the only thing she can see clearly.

"Hey, Little Grey." He says, or more accurately whispers. His voice is low, fading.

She buries her face into his shoulder. He feels warm. How is he so warm? She wants to just be wrapped into his warmth, to stay there and never leave. She inhales deeply - he smells like the woods, like mud and dirt, and even though she tries to ignore it she smells blood.

For a while, they sit in silence. She doesn't know if it's because they have nothing to say to each other or because they are so tired. How long have they been out there? Days? Weeks? Months? Time seems to blend together, the changing light the only sign it's passing at all, and she quickly lost count of sunrise and sunsets. Somewhere, a woman screams. She immediately knows its Meredith. Is it normal to recognize the sound of your sister's scream? Because she could pick Meredith's out of a line up. She tries not to think about what must've happened. She wonders if someone died - Derek, or Cristina maybe, or - dare she say it - Meredith herself. The thought makes her want to shudder. "We're gonna die out here," She whispers. She thinks it's the first time anyone has said it out loud. They all knew it was true, had it in the back of their minds, but none of them ever spoke the words. They're dying.

Next to her, Mark lets out a long, shaky breath. "We're not dying." He says with as much force as he can muster. "We're...we're not done yet. You and me...we're gonna get out of here. And we're gonna get married. You're going to be...a great surgeon, Lexie. And we're gonna have two or three kids..."

A smile comes to her face. "Siblings for Sofia,"

He smiles too, and nods. "Right. A sister and two brothers. And we're going to be so happy, Lex. Because I love you, and we're meant to be."

She feels her eyelids flutter closed - because God, she's so tired. "Meant to be..." She repeats, as dreamland overtakes her, the image of her and Mark and a family and a future bright in the darkness of her mind. And she sleeps, falls asleep in the arms of the man she loves, the man she will always love.

She never wakes up. Neither does he.

Time passes. People talk about the lives lost in the crash. Meredith Grey, the second generation of surgical greatness, and her husband Derek Shepherd, the best neurosurgeon Seattle had ever seen. Cristina Yang, a great talent for cardio, wasted potential. Arizona Robbins, the happy, perky peds surgeon who brightened everyone's day.

But when they talk about them, they are not just great surgeons. They are Mark Sloan and Lexie Grey, the tragic love story of Seattle Grace Mercy West.

six.

When he gets home, he is immediately met with a small set of arms grabbing him tightly around the legs.

"Daddy! You're home!"

He smiles as his oldest son practically pulls him into the house, dragging him along behind. Greyson is only six, but he is very forceful - his wife always jokes that he can never say no to him, and that's probably true. What can he say - Greyson is his first little boy, and when he looks into those eyes that are so much like Lexie's, he can't say no.

Caleb meets them halfway, with a chorus of "Daddy!" and grabbing onto him too, because at four he wants to be just like his big brother. But honestly, it doesn't bother Greyson much - he loves an adoring audience, which Caleb is always more than happy to provide.

His boys lead him into the kitchen, where the love of his life and his new baby girl are. His wife got home first today, so she is making dinner (just for four because Sofia is with Callie and Arizona tonight and their youngest is still breastfeeding), stirring the pot with one hand and cradling four month old Susie with the other. The little baby is fast asleep, her impossibly tiny thumb in her mouth, and her soft, downy brown hair is just beginning to peek out of her cap, which is slightly askew.

He lets go of his son's hands as they run off to play before dinner, a game of Legos and dinosaurs and make believe. He approaches his wife from behind, and she lets out a slight gasp as his arms wrap around her waist. "Hi," He whispers, pressing a series of kisses to the sensitive skin of her neck.

She laughs as she melts under his touch. "Hi," She says. She stops her stirring, dinner momentarily forgotten, as she turns around, moving both of her hands onto Susie's back as she kisses her husband. The baby girl stirs between them, and a smile graces her tiny lips as she sees her father.

Lexie's attention is diverted back to Susie as she starts to fuss. "Are you awake, my sweet girl?" She croons. "You're just happy cause Daddy's home, aren't you?"

She smiles at him, and he reciprocates as he scoops his youngest child up into his arms, and holds her close. Mark never thought his life could ever be as perfect as it is now.

But perhaps this was just meant to be.

In case you couldn't follow, the scenarios were:

They aren't on the plane when it crashes

Lexie still dies, but Mark lives

Lexie lives, but Mark still dies

They both live, but Lexie becomes paralyzed

Everyone dies in the woods

They both live and get their happy ever after