Thank you, thank you, thank you for all the reviews on the last chapter, and all your guesses.

So here are some answers, and more questions.

He's rarely felt as helpless as he does now, watching tiny limbs flail in anger, shrill screams assaulting his ears, Mark trying to restrain her so she doesn't hurt herself against the floor, the walls, the counter.

"Help." he manages to grunt, but before he can unfreeze himself, Addison is shouldering him out of the way, folding herself onto the floor beside the huddled Mark and Rosalyn, murmuring soothing words as she rubs her back.

As he watches, Mark carefully releases his grasp on her arms, sliding her into Addison's lap, adjusting her leg so it doesn't jostle, sliding the hand fluttering madly against her thigh between his own, swallowing it up as he rubs soothingly.

It's orchestrated, perfectly coordinated, and they perform flawlessly like they've done it a hundred times over.

He kneels beside them, a hand rising almost of its own accord to brush back her tangled hair, and he's all too aware of Meredith's eyes on his back as Addison whispers to him.

"Get out."

She's still shaking in their arms, soft keening noises escaping her tightly clenched mouth. The first time it happened she wasn't quite two, and she'd left her with a new nanny.

Mark looks drained, tracing soothing circles against the little hand he's holding.

"It hasn't been this bad. Not since-" he trails off when she cuts her eyes to Alex, still standing there, looking unsure what to do. She puts him out of his misery by jerking her head at the door.

"Ro?"

She doesn't respond, just burrows closer instead and she wraps her in her arms tighter, pressing a kiss to the top of her head. Sensory stimulation; she hasn't needed it in a while.

"I'll go tell them it's okay," Mark says after a long while of her not saying anything, just breathing slow and deep against her daughter's trembling chest, hoping to slow her ragged breaths.

Mark's right, she hasn't gotten like this since last year. Not since...

"Don't go." she chokes, and then Mark is looking at her too, his eyes probing, and it's all she can do not to scream too.

"What happened?" he demands as he strides into the office, where Meredith and Alex are sitting, looking dazed.

"I don't know, we were just talking - Sloan and me - and I said something about how I'll probably need Addison to come with me to Malawi and she... she just flipped, man, it was crazy."

"You think it's -" he can't bring himself to say the word. It's too much, heaped on top of everything else.

"Autism? Nah, she hasn't shown any other signs..." he trails off, looking thoughtful. "That I've seen, anyway."

"Karev, you pathetic-" Mark says a word that would have made Addison wince as he slams into the room. "What the hell were you thinking?"

Alex holds up a conciliatory hand. "I had no idea she's so sensitive about being away from her mom, I thought-"

"Well, you freaking thought wrong, didn't you," he growls. "In future, keep your mouth shut if you don't know the whole story, Dr.Karev. She's not sensitive. You don't know the story behind this. None of you do. Because you haven't been around for any of it. "

"Then tell us," he snaps, pulling the heavy oak door closed and stepping in front of it. "Tell us this story you're being all secretive about, Mark, tell us why you won't let Addison go, tell us about Rosalyn. Just tell us so you can stop being so -"

"You really want to finish that sentence?"

His tone is menacing, and he's always been a little taller. But he has the upper hand here, he's Rosalyn's father, he deserves to know.

"Tell me," he pauses, thinks it over twice. Mark has never hit him before. But that was before everything, and he's never seen this Mark before. But he deserves to know. "Tell me...or I'll ask Addison."

"You're going back."

It's not a question, it's a statement. And it's true.

She smooths her damp hair back, feeling her relax a little as she gains control of her emotions. "Just for a few days, baby, and I'll be right back-"

"You're a liar."

The words are flat, disaffected, none of the inflection she's inherited from her.

"Honey, Zola's all alone there. She's scared, and wants her mom. And her dad."

When she looks up from her lap, her eyes are brightest blue, sheened with tears and achingly familiar. "He's my dad too."

"He is," she says cautiously.

"You never told me."

"I'm sorry I didn't, darling, but there are reasons-"

"He didn't want me?" she asks tremulously.

That was what I thought.

"Ro, you'll understand when you're older. He loves you, very much."

"Do you love him?"

From the mouths of babes...

"I...used to. But he loves you and so do I, don't forget that."

"But I don't know if I love him, yet." She can see genuine anxiety in her eyes, and feels a pang of sympathy.

"It's all right, sweetie, you can take your time to work it out. No one's expecting you to make decisions right away, we want you to concentrate on getting better, and no matter what-" she grins at her even though it takes considerable effort to contort her muscles into shape. "- you'll always have me."

And she tickles her ribs, eliciting a squeal and a torrent of giggles. "Stop!"

"All okay?"

"Almost."

She grabs desperately at her hand as she slides her off her lap. "Wait, Mommy, you didn't say yes."

"To what?"

"Don't go." she implores. "Don't go, because last time you didn't come back."

"Don't." Mark says urgently. "Derek, please. Whatever you do, don't do that."

"Well, then tell me what happened, Mark." he bristles, panic heightening his senses, he's acutely aware of how close Mark is standing, the curl of his fists, the look in his eyes.

"I can't." he snaps, backing away, running his fingers through hair shorter and greyer than he's ever seen it. "She doesn't want-"

"Addison never knows what she wants."

They share a look of understanding for a minute, but then his slate eyes shutter once more, and he shakes his head. "No."

He looks at Meredith and Alex, sitting on the desk, watching them like a tennis match. "Guys-"

"Sure." Alex says immediately, sliding off the desk at once. Meredith is a little more reluctant, her eyes boring into his, and he mouths please.

She slams the door on the way out and it rings in the silence that falls between them.

They were friends, the three of them. Close friends, until he distanced himself and the two of them grew closer than close.

But they were friends, and they've been through a lot together - they're the only two who knew him from cocky med student to terrified intern to a resident finding his footing, to the surgeon he is now. They've seen the lows and the failures and the falls and the defeat before his highs, and he's seen theirs, and they know things about each other not another soul knows.

Maybe they can be friends again.

God knows he could do with some of his own.

"Mark, please," his voice is different now, shakier than he'd like it to be. "Is Addison all right?"

"We just lost our daughter," she spits, pacing furiously. "And look at him, chatting away with his old buddies like we've got all the time in the damn world.""Meredith, I don't think it's like that, there's something big Sloan's not telling us-"

"Do you think I care right now, Alex, really? Do you? I'm sorry, okay, whatever, but look. Addison's in the wrong here, she kept his own kid from him for years and come on, do you really think he would have left her, if he'd known about the baby? Whatever is going on with her right now, she owes him."

"You don't know what it's like, over there." he says heatedly. "I've been there, I've seen what it can be like, and -"

"You're siding with her."

"Of course not. Just...wait, okay, wait for the whole story before you label her Satan again and run off to burn her at the stake or whatever it is."

"That makes no sense." she breathes heavily, slumping against the wall. "Neither do I, right?"

"Right."

His hand on her shoulder is warm and solid, pulling her into his shoulder as she sinks to the floor.

"She'll be all right, Mer. Everything's gonna be fine."

"I'm not leaving you," she sighs. She thought they were over this phase; she's not over it, she still wakes up sometimes with the scent of smoke in her nostrils but she thought Ro was over it.

"You did," she counters. "Last time, you did. And you promised me you wouldn't ever never go back."

"Imagine," she says slowly, groping for the right words. "Being all alone in a strange new place without anyone you know, wouldn't you want someone to help you?"

"Ye-es," she says doubtfully. "But... you have to come back." she burrows closer, sniffling. "Say you'll come back really really super quick."

"Really really super extremely quick."

"Really really super extremely." she sighs. "It rhymes, Mommy. But you will, right?"

Mark slumps onto a chair, rubbing his eyes. "She is...now."

"What do you mean? She's been there before, I worked that out. And something happened... something big. Mark-"

The other man looks exhausted, sunk deep in memory. "Yeah, it was big."

"Can you tell me about it?" he asks gently, scenarios racing through his mind, each worse than the first. And then worry, for Zola, alone in the same country that haunts Mark.

And Addison, who is - however grudgingly he admits it - the strongest, most resilient person he's ever met. He used to think she was infallible. But then he got to know her, and...

"She was...broken." Mark says, his voice tortured. "For a long time she was broken and she's just gotten whole again, and I can't, I can't let her do this, Derek, what if something happens and I know it's your kid on the line, I swear I understand, but -"

He stops suddenly, evidently at a loss for words. He gets up, heading to a filing cabinet on what, judging by the disarray of the desk, is his half of the office.

"Read," he says, slapping a plastic binder of like newspaper clippings and... police reports? Lab tests? into his hand.

"Read, and tell me if you can live with yourself if you send her back."

More answers in the next chapter, including issues not addressed in this one.It's scientifically proven I update faster when adequately stimulated by ... you guessed it, reviews!So let it rip. I'd love to hear what you did - and didn't - like, what you do - and don't - want to see.