Author's Note: Hello! So I stared this story a while ago and in light of recent Grey's events (don't read the author's note at the bottom if you don't want season 7 spoilers) I feel that I need to post something a bit happier. This story is kind of a rewriting of a scene in Season 5, called "Before and After," in which Addison almost spills the beans to Derek that Mark and Lexie are together. I always wished she'd gotten the words out; it would have made for a spectacularly awkward scene :)

Hope you like this!

Lexie Grey is standing a few yards away from the nurses' station, admiring her ribbon. Mark walks up to her, his behavior rather stiff and seemingly indifferent.

"Dr. Grey," he says, stopping a good five feet away from her. "It appears congratulations are in order."

"Thank you, Dr. Sloan," she says, smiling at him.

"I'd also like it acknowledged that I offer these congratulations professionally and respectfully…Without any innuendo or inappropriate body language," Mark says as Addison looks up from the nurses' station, studying the couple.

"Acknowledged, Dr. Sloan," she says, a smile still on her face. If someone who didn't know Lexie and Mark's secret history, which was currently most people, they would think that this was all just professional courtesy. That is, until Lexie leaned towards him, much too close.

"Do you know," she says, looking up at him and biting her lip seductively, "What's a doomsday sucker?"

He grins, leaning into her despite the fact that they're in public, about to speak. Addison takes this moment to make herself known, walking up behind Lexie and offering her hand.

Addie walks up. "Addison Montgomery," she says, introducing herself and holding out her hand.

"Uh, Lex—Lexie Grey," she returns, shaking her hand.

Addison's eyebrows rise as her eyes shoot to Mark's. He looks down, not making eye contact.

"Mark, Addie, Little Grey," Derek says, walking up to the trio.

"Little Grey?" Addison asks with surprise, glancing again to Mark. He just keeps his head down, rubbing his cheek nervously and pretending he doesn't notice her reaction.

"I am going to have to meet you at Joe's in a bit," he informs his ex. "I've got a craniotomy. Little Grey," he continues, turning to Lexie. "I hear you're going to be holding the doomsday sucker."

"Now?" Lexie is asking, looking at Derek eagerly. "Uh, great! Yea—yeah, yes! Yes, sir."

"OR two, I'll see you there," he says, nodding to Lexie. Lexie smiles, leaving their party and walking towards the scrub room. Addison smirks, watching her leave.

"Doomsday sucker!" Lexie calls out, her arms in the air. Derek chuckles before turning to Mark and Addie.

"So," Addison begins casually—so casually that Mark didn't pick up on her amused undertones, something that will surely get him into trouble. "Can you believe Little Grey and Mark?" She says, tilting her head in his direction and trailing off suggestively.

"Addison!" Mark warns, looking over at her, his face stricken. Derek's head, which had been looking confusedly at Addison, automatically swivels to meet Mark's worried eyes. Derek stares at him for a moment, completely speechless.

"Derek…" Mark starts, and then breaks off, deciding to wait for what he's going to say. After a moment, Derek closes his eyes, looks down, and a smile appears on his face. Mark looks, if its possible, even more worried.

"Well, I guess I shouldn't have expected anything different," Derek sighs, looking at his best friend. He isn't glaring or accusing, just simply stating a fact. Defeated. But that total superiority of Derek's gaze is what gets to Mark. The complete exhaustion in his tone. It's as if Derek is saying that Mark just can't help himself, and that he'll always be what he's always been. That he can't change, that he will always fail in Derek's eyes. Mark crosses his arms, defiant. Addison just looks on, amused, not realizing the mess she's just created.

"And why is that?" Mark asks, studying the neurosurgeon.

"Well, when I tell you not to do something, you just go ahead and do it. You can't help yourself. I would say it isn't your fault…But it is your fault."

"And you're just forming this opinion without any knowledge of the situation at all, are you?"

"I don't need any knowledge of the situation. I know enough already. This is just like any other time. I ask you not to, and you promise me you won't…but you just couldn't help yourself this time, could you?" Derek's condescension is tangible, and it sets Mark's teeth on edge. "Just like any other time," Derek mutters, shaking his head. Addison glances between the two, her smile faltering. She has no idea how the conversation went from Mark dating Lexie Grey to whatever they were arguing about in secret.

"Wow, that's insulting," Mark snaps, glaring at his friend. "And you've even got the basics wrong this time. First off, you didn't ask me—"

"Oh, really? Was that not me telling you not to get involved with—"

"It was Meredith," Mark growls out. "It was Meredith and you know it. Hell, you told me it was her who had the concerns. But, just like you two, your concerns are always misguided. Lex doesn't need protecting. She's fine," he spits out. His eyes flash as he speaks again. "And am I really that dangerous? Do you really think that being with me would corrupt her or something? I mean, I get it, I slept with Addie and you were pissed. That's reasonable. But come on! Addison's not here anymore, Derek, and it's not like I did anything to Meredith! But you, as always, need someone to pin all your pent-up anger on—and I just happen to be the perfect target."

"Um, in case you haven't noticed, I am still standing here," Addison says, waving her hand in the air, trying to break up the animosity. She realizes too late—as a sudden awareness hits Mark—that she can't do anything to stop their fight.

"You did this on purpose, didn't you?" He accuses Derek. "You knew once you said anything I wouldn't be able to leave her alone. You set me up for this, just so you could prove once again how much better a guy you are than me! I told you it was your fault! I told you I never thought about Lexie like that till you brought it up!"

Meredith was just joining them at the sound of Mark's shouts.

"What?" She asks sharply, her eyes shooting to Derek's face as she walks up to him. "You knew he was sleeping with her?"

"I didn't!" Derek says, defending himself.

What the hell is going on here? Addison thinks to herself. I've been caught up in the middle of some crazy pissing war/turf fight?

"He," she says, motioning to Mark, "just said that you brought up Lexie to him! After I told you to keep him away from her!"

"I didn't say it like that! It was his own fault for having sex with her!"

"It was not!" Mark said, glaring to the two of them.

"Oh, I'm sure," Derek retorts scathingly as Meredith rolls her eyes. Even Addison has to suppress a giggle.

"It wasn't!" Mark replies vehemently. "Go ask her!" He offers, pointing to the OR. But no one had to make a move to find Lexie.

"It's true," says a voice form behind them. They all turn to see little Lexie Grey standing there. She was standing just on the periphery, by the OR doorway, but well within earshot. She had just been about to walk in when she heard the two mens' angry voices drift back to her.

"What?" Meredith, Derek, and Addison ask together in disbelief.

"I went to his hotel room—he didn't come after me."

"Lex…" Mark says quietly, his expression and tone telling her that she reallydoes not need to go there.

"No, it's fine, Mark. Seriously. I'd rather we get it all over with here and now." She takes a breath. "It's not his fault that we slept together. I mean, obviously, he—he had a part in it, but I was the one who instigated it." She pauses, her eyes focusing on Derek. "You can yell at me, if you want, Dr. Shepherd," she says, her voice sounding weary. Derek just gapes at her, unable to speak.

"Or," Lexie continues, her voice gathering anger and her expression turning stormy, "I guess I should talk to you, Meredith," Lexie snaps, turning towards her half-sister. Now it's Meredith's turn to look guilty as Lexie glares at her. "What say do you have in who I date or sleep with? What right do you have to just barge into my life and try and be my sister whenever you want? I gave you plenty of chances and you failed on every try. Well, that's not totally true," she says with a fake laugh, barreling on without letting Meredith get in a word edgewise. "You didn't try. And you still don't try. Why should you get to flick a switch and decide to try and control my life?"

"I was trying to protect you!" Meredith half-shouted at her, stepping forward to defend herself. "And it's not my fault I'm a shitty sister; you know as well as I do that you're the daughter Thatcher wanted, not me. And what right did you have, thinking you could just show up here and think that I would know or want to know who you were? Yeah, things have changed since then, and I feel badly about how I acted, so I tried to do something nice, okay? I was trying to help you—the only way I knew how. I was trying to protectyou."

"Protect me from what? Him?" She says, jerking her head towards Mark. "Please," she rolls her eyes. "He's harmless."

"Hey!" Mark protests, looking indignantly towards his girlfriend.

"Yeah, maybe to anyone else, but not to you!"

"Oh, what am I to you, some stupid fragile flower that will crack and shatter into a million pieces at the slightest touch?" Lexie spits at her sister. "You have no idea who I am."

"Right. Right. Sure, I don't know who you are. You grew up like a normal kid. Your parents were there for you, you had friends, boyfriends, normalcy. Mark didn't. Mark is me."

"What? So what if his family sucked as much as yours? That doesn't make him you."

"Yeah, I would like to add that," Mark interjects, holding up his hand, "while our childhood experiences were vaguely similar, Grey, we are not the same person."

"Whatever," Meredith says, barely sparing him a glance. "This still doesn't explain why neither of you decided to tell one of us. You see us everyday. It wouldn't have be that hard."

"Oh, really?" Lexie asks, her voice venomous. "Not that hard? Yeah, right. It would be horrible and you know it. It'd be you sitting there on your high horse, looking down on me, while I try to explain it all to you. You'd never accept it—never accept us—even though our relationship is the same as you and Derek. Except," she glances apologetically at Derek, "Mark's not married."

"Ouch," Mark mutters to Addison.

"I would've listened!"

"Oh yeah?" Lexie challenges.

"Yes! As—As much as was expected, that is…"

"Exactly. As much as was expected—which would be zero understanding on your part."

"Okay, fine, I get it. You didn't want to tell me…But Mark could have!"

"Right, Grey," Mark says, reprieving Lexie and stepping in the defend himself. "Like it would have been any better coming from me." Meredith just glares at him.

"You could have spoken to Derek. He'd listen to you."

At this Mark lets out a short laugh, his eyes shifting to Derek. "He'd have punched me before I even got the words out."

"Besides," Lexie continues, too fired up to stop now. "I'm not the one who wanted to keep it a secret! I told Mark to tell Derek. It's not my fault that he chickened out!" She paused for a moment, throwing her boyfriend a sheepish look. "Sorry."

"No worries," Mark returned, grinning despite himself.

"So you were never going to tell me?" Meredith yells, drawing everyone back into the fight.

"No!" Lexie yells back indignantly. "I…was! I was going to tell you."

"Well?" Meredith puts her hands on her hips. "Why didn't you?"

"Because…Because…" Lexie falters, looking to Mark for help before facing her sister again. "Because I knew this is how you would react! I knew you wouldn't get it and I knew you'd judge us without even thinking about it first."

"That's because I don't need to think about it. I know what's going on."

"You have no idea what you're talking about."

"Yes, I do! You said it yourself—do you think what you're doing is so different from Derek and I? You think you're not acting the same way I did?"

"Well, if our situations are so similar, why are you so hypocritical? If you and Derek worked out, why can't Mark and I?"

Derek and Addison try and fail to contain their laughter.

"Because," Meredith explains, trying to reason with her sister. "It's different."

"Oh, well that clears it all up," Lexie retorts sarcastically. "Come on, give me one good reason why we should stop seeing each other and maybe I'll see your side."

"Because…" Meredith pauses, wracking her brain. She knew they shouldn't be together—she had a feeling—but she just couldn't put it into words. "Because…" Meredith tried, but just ending up trailing off again.

"Ha!" Lexie yells, pointing her finger at Meredith. "You can't even come up with one reason why—"

"Man whore!" Addison yells impatiently, surprising everyone.

"What?" Lexie says, startled by Addison joining in the fray. Meredith turns around, silently pleased that Addison was the one to blurt it out and not Meredith.

"He's a man whore!" Addison repeats, stepping closer to Lexie and leading her a few feet away from the others. "Come on, Lexie," she tells her quietly, almost a whisper. "Think about this…Will you two really last?" Addison asks gently, her face displaying all the hurt, sorrow, and betrayal that Lexie knows she must've felt when she was with Mark. But, beneath it all, Lexie could swear she could see a flicker of happiness. And happiness was all that counted. Lexie sighs, looking down before facing Addison, speaking quietly as if trying to block all the others out.

"Look…I—I know that you guys didn't work out. I know that he cheated on you and I know that you aborted his baby," Lexie admits quietly as Addison's hurt eyes shoot to Mark's.

"He told me," she continues quietly. Addison's face falls as her eyes dart to Mark and then back to Lexie. How could he tell her? By the time her eyes meet Lexie's, her face was once again composed, a perfect mask.

"And?" Addison presses.

"And…" Lexie hesitates. Addison raises her eyebrows, waiting for a response. What she gets, though, is far from what is expected. "And he said we weren't like that," Lexie says quietly. Mark takes over, realizing that Lexie is embarrassed speaking for him in front of his ex.

"I meant what I said, Addie," Mark says, stepping up to stand beside his girlfriend. "I don't want to do that anymore. I don't want to be the guy who sleeps around. I want…" He sighs, gathering his thoughts. "I want someone who wants what I want. And what I want is to be with Lexie." He turns to Derek and Meredith, leaving Addison speechless. So this is what Mark's like with her…

"And if neither of you can accept that," Mark says, addressing Meredith and Derek, "then I'm sorry, but that's too bad. We aren't going to hide for your sakes'."

And with that, Mark walks off, heading to Joe's, leaving behind a speechless Addison, Meredith, and Lexie. Lexie never thought he'd actually tell Derek…She thought he'd just find out somehow…But seeing him stand up for them in front of his best friend…It felt great. Lexie found herself smiling as she watched him walk away.

Derek, for his part, is fuming, but managing to control his anger—he can't go into surgery pissed off. He places the chart gently on the nurses' station, using great not to slam it into the counter. He sighs, resting the palms of his hands on the counter before pushing off, his face cleared.

"I have a craniotomy to get to," he informs the three women, his eyes on Lexie.

"Right," Lexie says quietly, knowing what he means. She turns around with another word and heads to the intern's locker room. Well, at least Mark told him, Lexie thinks as she walks away. There'll be other craniotomies.

"Dr. Grey," Derek calls out, stopping Lexie in her tracks, not even twelve feet away.

"Yes, s—sir?" She asks hesitantly, waiting for the yelling to begin all over again. But what happens is far from what she expects.

"You're still holding the doomsday sucker, aren't you?"

"Um, I," she falters, her eyes looking from Meredith to Derek. When Meredith won't meet her sister's eyes, Lexie walks forward. "Of course," she finishes confidently. Derek just nods, and Lexie heads towards the OR, this time walking all the way in.

"Derek," Meredith warns, her eyes boring into the back of his head. Derek turns around slowly, facing his past and present relationships. "You can't—"

"She won," he explains tiredly. "She should get to scrub in."

Derek walks off, leaving Addison and Meredith alone together to digest everything that's happened. After a moment of silence, Addison grabs her purse from by the phone.

"Well, I should—go to Joe's," she says, excusing herself. "Naomi and Sam are waiting…"

"Right. Of course," Meredith nods. Addison starts to leave but stops when Meredith calls her name. "You'll tell Derek I went home, right?"

"Sure," Addison answers. She gives the other woman a nod before leaving and heading down to the bar. Meredith stands alone, musing over her thoughts.

…

Author's Note:

(SPOILER ALERT!)

Okay, I just watched "Adrift and At Peace"...And can I just say that I LOVED IT? I was really worried that they wouldn't get Mark and Lexie back together in a realistic way (I have no idea why I bother ever doubting the Grey's writers...They always get the job done)...And just...*guh* I LOVED IT. I thought it was so perfect, and it totally fit both of their characters. So romantic and cute... 3 And I totally loved Lexie telling Jackson to "deal with it." That made me smile. (Side note; Am I the only April/Jackson shipper out there? I think they'd be cute, and I've kind of always seen it...) Besides all the great Mark/Lexie stuff, I really loved Eli, even before he asked out Bailey. I thought the Teddy thing with the dying patient was also kind of cute. Though it was heartbreaking, I think how they left Callie and Arizona was good. I don't think Callie would forgive her right away...Though slamming the door in her face was a little too harsh. But I see where she's coming from.

Even though we have to wait till January...At least we know Mark and Lexie are together. :D I've been waiting for this for like ever. I'll definitely be re-watching this episode. :)

(SPOILER OVER!)

Anyway, with this story, I'm planning on continuing it after this chapter. I'm not sure how far I want to go with it, but you can count on at least two more chapters. Thanks for reading, and please leave a review and tell me what you think!