Author's Note: Note that some of this chapter was heavily inspired by the Grey's/PP crossover many seasons ago (and even includes a bit of ... lightness? among the angst); you may recognize dialogue and set pieces, even with the timeline shifts. Thanks to all who have been reading and reviewing. This story has been plotted for years, but you've inspired edits and tweaks to make sure it's working (or try to).

what were all those dreams we shared those many years ago?

She finds herself avoiding the cracks in the linoleum floor of the hospital's hallway, carefully arranging the pointed toes of her modest heels like Annabel sometimes does on the sidewalks at home.

Step on a crack, break your mother's back.

She can do this, one moment at a time. She can procure coffee for herself and for her husband, she can return to her daughter's bedside, and she can wait the endless clock ticks that mark their hours from now until the moment her daughter can finally start to get better. Until she can exhale again; until things can be normal again.

Normal.

Today is Thursday, which means – if things were normal – that Annabel has ballet and Max has what the studio likes to call terror hour, which is when the numerous little siblings of little dancers entertain each other in the dressing room with none-too-graceful pushing and shoving. She smiles at the memory. They didn't want overscheduled Manhattan kids, that was what they said, but almost all of their activities, their schools, home, their lives are within a twenty-block radius that makes it incredibly easy to pop in on her children and snatch family time whenever they can. Now she wants to go back in time and shake that younger, more naïve version of herself, the one who would duck out of the hospital in time to watch Annabel twirl through a two-way mirror, Max propped on her hip, blackberry in one hand to monitor a patient in early labor.

Normal takes work, but she knows this – it takes scheduling and help and time. It takes sacrifices they have always been more than willing to make. Ida has been with them since Annabel was a baby. She has become more than a nanny over the years; she's the closest thing they have to extended family. Ida offered to come with them, offered to do anything she could to help. Addison promised to send her regular updates, but she's hesitated every time her fingers hovered over her blackberry. Talking to Ida about it makes it seem too real.

It should be an ordinary Thursday. It should be normal. If she knew how to pray, she'd pray for a lifetime of ordinary Thursdays.

But she doesn't know how to pray, doesn't feel right now like she knows how to do much of anything except how to put one foot in front of the other, avoiding the cracks, and that's how she walks all the way to procure two bitter cups of coffee that they swallow like medicine.

Now she and Mark sit on opposite sides of Annabel's hospital bed, a cruel parody of the way they used to lie in their big bed all together, Mark and Addison propped on their elbows on either side of baby Annabel, watching her sleep. They would exclaim over every soft sound that escaped her little pink lips, every time her tiny nose twitched or her impossibly small fingers curled. Everything was new, everything was miraculous. I wonder what she's dreaming about, Addison would ask sometimes, thinking that this, the three of them together, was her dream.

Dreams end. She swallows coffee knowing it won't work on the exhaustion deep within her bones. She twists and untwists the hem of her blouse. In her mind she hears Mark telling her what Derek said about Max.

He's your clone.

She's been haunted all day by the conversation she heard between Derek and Meredith. So Derek wondered …

But he didn't ask. He never asked.

Meredith's tone suggested it was something they had been discussing, something Derek had raised – did he really think Annabel could be his?

She almost told Mark what she overheard; she's in the habit of total honesty with him, but it was her idea to call Derek. Mark agreed, but it was her idea. Derek is Annabel's only hope, their family's only hope – she can't let Mark lose faith in Derek now.

And there was more to the conversation, there are parts she's tried to forget. She listened to Derek and Meredith arguing quietly – even with their emotions high, it seemed they still didn't want to wake up Annabel, which she can't help appreciating.

You need to stop this, Derek. You said you would stop this.

Look at this. Meredith, look. The DOB was wrong on the chart they sent from Sinai – that four should be a three. Do you know what that means?

That someone should be fired for sloppy charting?

It's math.

No, it's not math, it's something else, it's you not being able to get past – it's just – it's something you need to stop.

You don't understand.

I do understand, Derek, but you can't …

And then she heard Meredith's voice, firm and set, I'm going home to our son now. With stress on the word son.

Addison is looking at Annabel but she sees Mark's familiar shape in her peripheral vision, and a flood of protectiveness fills her – she can't tell him about what she overheard, not when they have so much to deal with. Not when Mark has been so much better at compartmentalizing with Max, preserving what he can of Max's daily routine. She needs to lean on him and she can't give anything else to make it worse.

It's math.

Well, she was always in charge of that particular brand of marital math, and his miscalculation makes everything takes on new meaning now. Derek smiling at Annabel's bedside. The gentle way he examined her, his questions. His hand brushing back her dark curls. Did he think – did he always think – was that why he agreed to attempt the surgery in the first place?

"Addie?"

She jumps, startled. Mark is looking at her over the top of his coffee cup, his gaze strong. They don't keep things from each other – well, that one thing notwithstanding – and she's pretty sure he can tell she hasn't mentioned something.

"What is it?" He asks the question gently, his expression so understanding that a pang of guilt flushes her cheeks.

"Just … everything," she says, which isn't exactly a lie, but she feels worse when he reaches for her hand and squeezes it reassuringly.

Just everything. Just Derek did something and I don't know what it is and I don't think I want to know what it is. And I don't want you to know either. Just that.

She looks at Annabel's heart-shaped face, relaxed in sleep. Long dark lashes resting on rosy cheeks, soft dark curls spilling over her shoulders. She looks at her and sees her baby, her firstborn. She sees a smaller version of her own mouth, the faintly upturned nose from Mark's baby pictures, the tilt of a little chin that is neither of her parents' and both of theirs at the same time. She looks at her daughter and sees the best thing to come out of the worst thing she's ever done. Her daughter made everything worth it. Addison adores Max and knows their family wasn't complete until he was born, but Annabel is the one who made them a family. She looks at Annabel and sees the center of their world.

And wonders what Derek sees, when he looks at her.

"I'm not pressuring, Addie, I'm talking. There's a difference."

"I know there's a difference. And I know which side of the difference you're on." She stares out the window in sunglasses, into the late autumn glare. He just loves to corner her in the car when she can't go anywhere, and Thanksgiving traffic on the Merritt pretty much guarantees a captive audience.

"Are we going to argue semantics or are we actually going to talk about this?" He signals, passes a slow-moving jeep in the middle lane.

"Do we really have to talk about this right now?"

He glances at her, then back to the road. "When do you want to talk about it, then?"

"I don't know!" She's much louder than she intended and she sees him flinch, then feels even worse. Nothing like this conversation to make her feel like a terrible wife, and now she's yelling at him too... "Derek, I'm sorry."

"Okay. It's okay." He frees a hand from the wheel to pat her thigh through the dark wool of her slacks. "Just … don't yell at my mother if she brings it up?"

"Well, why does she have to bring it up?" She mutters this, turning again to look out the side window, and she can feel him sigh just through the warm palm resting on her leg.

"She's a mother. It's what they do."

"My mother doesn't do it."

He's tactfully silent for a moment, but then he starts talking again and it's in that gentle tone that makes her feel teary even when she has no reason to be upset. "I want to have a family with you, Addison."

"I want that too," she whispers, fingers tight in the leather door handle. Outside, red and gold leaves line the highway. "I do, Derek."

"I love Nancy's kids, and Lizzie's and Kath's but … I want our own, Addie. I want redheads," and she can't help smiling at that. "And I want them to laugh like you and question every single thing I say like you and I want them to be ours."

He's so open; not for the first time she admires how he can just … talk about things like this, his feelings so close to the surface. She knows how lucky she is, to have him, but…

She draws a deep breath. She can do this. She wants the same thing he does, of course she does, except that she's the first person in their class to start a second fellowship, a few months ago now. And Dr. Millberg – the leader in the field, that's what everyone says, called her exceptionally promising. No, more than that, he said she was the best he'd seen in years. She still has 18 months left before she's credentialed. If she gets pregnant she'll have to drop out and someone else will take her place. The fellowship can't wait.

She opens her mouth to say something reassuring, steady, to make it all better, but her voice comes out thin and shaking instead: "I'm only thirty-two, Derek. We have so much time."

"Addie." Mark touches her arm.

"I need to … check on Max," she blurts. She stands shaking in front of the hospital directory, then walks in the opposite direction of the playroom. Walks until she's found the small, empty chapel. And then she sits down on a hard, polished bench and squeezes her eyes tightly closed. Isn't this what she's always feared? Their mistakes, coming back to haunt them? Annabel, the best thing that ever happened to them, lying in a hospital bed while her life hangs in the balance?

It's all my fault.

Trying to remember the few services she attended at the First Presbyterian Church as a child, she rests her head in her hands, then sits up and folds her fingers together. This looks easier when other people do it. She's considering whether her fitted skirt leaves her enough wiggle room to kneel, and reflecting on the fact that she won't care how ridiculous she looks if it can help Annabel, when a voice she doesn't recognize interrupts her thoughts.

"You okay?"

She turns around to investigate. It's not God.

It's a tall, dark-haired woman in a lab coat and scrubs, large dark eyes focused on her with concern.

"I'm okay," Addison responds. "Well, I'm trying to figure out how to pray, but I'm a WASP and I've only ever gone to church at Christmas." It is, she realizes with a pang, the only childhood tradition she's allowed herself to repeat with her own children. Everything else she consciously set aside. Everything else she refused.

The other woman smiles. "I'm Callie."

"Addison."

"Addison…Sloan, right? I heard about your daughter."

"Yes. Well, Montgomery, actually, but…yes." She is Addison Sloan sometimes, unofficially, at the playground or the park, to the parents of Max and Annabel's classmates, but she's been legally Montgomery for more than seven years.

I don't need your name. I just need you.

The other woman, Callie, doesn't look confused by Addison's stammering answer, just smiles. "Your son has made an impression too."

Addison can't help smiling back. "I hope he hasn't been too much trouble – he might be too used to coming to work with us. He didn't bother you…?"

"No, I just know someone in Peds. Pretty well, actually. I'm Ortho myself. Kids give me the wiggins. I mean, no offense." She offers Addison a surprisingly reassuring smile. "So…you're praying?"

"I - " she looks around. She's not sure why she's saying this, but the words tumble out of her unbidden, and maybe she's just been waiting for someone to hear her. "I … cheated on my husband, and I got pregnant with Annabel while I was still married to him. I was going to have – I mean, I almost didn't have her. And now she's sick – and I don't know how to pray. So yeah, I'm, uh, I'm trying to figure out how to pray."

He's standing silently outside the Park Avenue office building when she gets there. She's ten minutes late; she doesn't – or can't – ponder what that means for a woman who's always ten minutes early. She doesn't even see him until the uniformed doorman reaches for the heavy glass door. Mark doesn't say anything, just stands there with his hands in the pockets of his leather jacket – it's unusually cool, maybe that's why she's shivering – and then she rests a hand on the cold glass of the doors and turns to him.

"Aren't you going to say anything?" she asks.

"You already told me I don't get a say." He's half turned away from her.

"You said you weren't going to try to talk me out of it." Her voice quavers on the last word. She's not exactly sure she wants; theoretically, she has time to decide – well, medically, legally, every way except emotionally, she has time.

"I'm not going to try to talk you out of it." He shoves his hands deeper in his pockets and seems to be forcing himself to meet her eyes. "That's not why I'm here."

"Why are you here, then?" She clenches shaking fingers together.

"I'm coming with you."

"What?"

"We got into this together. So." And he finally meets her eyes. His are hooded, tired. And he's unshaven – not the artful, careful scruff she's seen him perfect over the years, but the shadow of a man who missed his morning routine. Maybe didn't even sleep. "If you want to get out of it, Addison, then let's…get out of it together. Whatever you need, I'm, uh, I'm here."

For a moment she just stares at him. Then the strap of her bag slides from her fingers as she lets herself fall against him, the tears she's been holding back all morning finally starting to fall. Crying on the street – Bizzy would have a fit. The doorman tactfully turns his back but Mark doesn't say a word, doesn't shush her, just holds her against him in the damp late summer air. Finally, she draws back.

"I'm sorry."

He brushes some moisture from her cheek with his thumb. "It's hard. I know. You ready now?"

"Yeah." She hefts her bag back over her shoulder, swipes a last tear away, and tucks her free hand into the crook of his arm. "I'm ready to go home."

"I was going to do it." She's holding her head in her hands, but she knows Callie's still behind her, listening. She can hear her breathing in the still, stale air of the small chapel. "Or, I don't know, I think I was. I was so close. I was at the door. I could have."

"But you didn't."

"But I could have. And now she's - and now-" her voice breaks. "So I'm trying to figure out how to pray," she says again.

"You think God did this?" Callie asks, her voice serious.

"I wouldn't know."

"Well, I do know." Callie moves into the pew next to her, sits down. "God doesn't give little girls brain tumors because their mothers considered all their pregnancy options."

She swallows some of the tears she's been holding back. "Yeah?"

"Yeah." The other woman, at least, sounds certain. "And I had twelve years of Catholic school so I guess you'll just have to believe me."

She draws a shaking breath. Her hands are still folded on the back of the pew in front of her. She wants to believe it.

"Did you come here to pray too?" Addison asks.

"Yes. Well, sort of. To think, at least. Because – look, you have a lot going on, I don't want to bother you with this."

"No, tell me. I could use the distraction."

"I might be a lesbian."

Addison's eyes widen. Maybe it's all these years without close girlfriends, but this woman certainly is … direct.

She seems to want an answer, so Addison says tentatively, "well, that's … not a problem, is it?"

"I'm not sure. Is it? Thirty-five years of boys, boys, boys and now I might be a lesbian, so I'm confused, so I'm going to pray. Or think, at least."

"Why do you think you're a lesbian?" She's curious now.

"Because after thirty-five years of boys, I can't stop thinking about a non-boy. A non-boy with animals printed on her scrubs. Did I mention kids give me the wiggins?"

"You did."

"I mean, I'm sure your kids are great, but kids in general … and there are animals on her scrubs, Addison – can I call you Addison?"

"Sure."

"So ... now you understand why I might be a lesbian."

"I guess I do." Addison leans forward, resting her chin on her folded hands.

"Addie?" And then Mark is there, in the doorway of the chapel, brow furrowed with curiosity. "Are you - praying?"

"No." She hoists herself to her feet, automatically straightening her skirt. She turns to the other woman. "Nice, uh, nice meeting you."

"Likewise."

"Good luck with … everything," Addison says in lieu of good luck with the lesbian thing.

"Who was that?" Mark rests a hand on her back as they walk down the hall.

"A messenger, maybe." She looks up at him.

"Yeah?" He runs his thumb along her cheekbone. He can always tell when she's been crying. It's certainly more frequent these days.

"I just felt like going in there," she says, even though he didn't ask, even though he rarely – if ever – asks her to justify herself. Suddenly she realizes he's come looking for her, instead of sitting with Annabel, and she stops walking so quickly Mark almost trips over her.

"Did something happen? How is she?"

"She's sleeping. She's fine," Mark reassures her, and they both pretend fine means anything that's not terrifying. The same, that's what he means.

"Actually, I was going upstairs to find Max because…" he reaches into the pocket of his jacket and produces a small wooden traffic light. "I think he left this in Annabel's room."

"Doesn't that belong in the playroom?"

Who's upstairs but Callie, the woman from the chapel, talking to the blonde Peds doctor her son adores. Addison gives Callie a nod of recognition and gets one in return.

"Did you forget something?" Mark squats down next to Max to offer him the traffic light and Addison watches them from a few feet away, smiling.

"Your husband is hot."

"What?" Addison starts at the unexpected voice, looks up to see Callie standing in front of her, one hand on her hip, her gaze on Mark, who is now cross-legged on the carpet fitting two train tracks together while Max offers advice.

"I'm sorry, that's totally inappropriate right now, I know, but see, I can still see that, and if I were an actual lesbian, I wouldn't see that, right?

"I don't know." Addison smiles in spite of herself as Mark and Max. "I mean, he is."

"Yeah, he is." Callie scrunches up her nose. "But…so's she."

"She? Oh," and she sees where Callie is looking, and puts two and two together, finally. "So that's your girl."

"My girl? She's not my girl. No. I mean, I don't know, maybe she's my girl." Callie closes her eyes. "How inappropriate am I being right now?"

"Honestly, it's … kind of refreshing. But I need to get back to Annabel. And…" she can't help smiling as she sees her son turn his adoring gaze to Dr. Robbins, who is making a yellow wooden school bus talk in a high, squeaky voice, "Maybe don't tell Max about his competition."

She and Mark don't discuss or plan it; like so many other times, they just proceed in sync, until all three of them are settled in Annabel's room. Holding a quiet Max on her lap, she watches her daughter sleep and thinks about what she overheard Derek say about the timing of the surgery. Time feels so short right now, so precious and yet so terrifying, the red numbers of the seizure clock blinking cruelly from the wall.

"Mommy," Max murmurs, fingers reaching for her, not upset, just … there, and she holds him closer, whispering reassurances. For the hundredth time she wonders if they've done something terrible, bringing him here to this sterile world of humming machines and fear and his energetic older sister, the one who taught him to skip rope and jump into the pool, motionless on a bed. But she cradles his sandy-blond head and tells herself that it can't be wrong, can't be completely wrong, not if all four of them are together.

"Addison." Mark says quietly, and she glances up. He gestures with his chin toward the seizure clock on the wall.

22:00.

She's twenty-two hours seizure free. Just two more. If her almost-seven-year-old can go just two more hours seizure free, Derek can operate. He can fix her, make her their Annabel again, and then they can go home to the cocoon they've built, to the park and the skating rink and the office where when she sees patients on Sundays, Annabel twirls on the stool at reception and reads aloud to Max.

Just two hours until they can start fixing this.

She allows herself to feel a glimmer of hope and, with it, a tiny bit of the tension in her shoulders lessens. It's dim in Annabel's room, and she can feel herself starting to doze, the warm sleepy bundle of Max on her lap lulling her into comfort.

Light gushes in from the hallway without warning and she squints, adjusting. The chief is standing in the open doorway.

Richard's face is set and grim. There's a file in his hand. Addison swallows hard, feels Mark tensing next to her.

"Richard?"

The chief's tone is as serious as she's ever heard it: "We need to talk."

Reviews are warmly welcomed and greatly appreciated.

Title from Pearl Jam's The End.