Around the Sun

by BlossomOfSnow

Derek & Addison divorce when she first hands him the papers. Derek hasn't forgiven her & she's trying her best to pick up the pieces. They don't see each other again until they're both commissioned to work on a clinical trial in Washington DC, which has them spending more time together than they'd want. An ADDEK story set in the four seasons. TRIGGER WARNINGS inside. COMPLETE!

1. Spring

A/N: Are there still any Addek shippers out here in 2020? I know this ship has sailed so long ago, but Addek is still my OTP. Being stuck at home during this pandemic made me revisit my favorite angsty Addek stories, and consequently made me want to write one myself. This is a 4-part telling of an Addek reconciliation story set in the seasons, where Addison never moved to Seattle and they divorced immediately after her TTTS case. The chapters are intended to be long as I wanted this to comply with the four seasons.

Let me know what you think!

TRIGGER WARNING: mentions of non-graphic sexual assault in later chapters.

...

The wheels started turning in the spring. In Seattle the rain showered and the flowers bloomed, and Derek Shepherd was at the top of his game.

With the blossoming of the flowers, Derek was invited to co-lead the clinical trial on in-utero spina bifida repair funded by the Kennedy Foundation. He was thrilled. Such a grant was prestigious, and to lead a nationwide trial that spanned 4 states and 4 huge institutions was an amazing feather on his cap. Everything sounded perfect—monthly trips to Washington DC where he would perform surgery at George Washington University, the chance to collaborate with some of the country's best doctors, and a generous benefactor that would see through the trial until publication. Truly it could not get better than that.

But of course, nothing is ever perfect. The catch for this amazing deal? The co-lead was a world-renowned OB-GYN and neonatal surgeon he had the most unfortunate pleasure of calling his ex-wife.

Yup. He would be working closely with the one and only Addison Forbes Montgomery, the woman he was married to for 11 years before she decided to screw his best friend on his favorite sheets. He hadn't seen her since the divorce. She flew to Seattle under the pretense of a TTTS surgery, but was really only there to serve him divorce papers. He had signed right away. No second thoughts. There was no use dragging out a marriage that they were both miserable in, and he was downright angryhurtbetrayed by her infidelity that he couldn't at that time even consider forgiving her.

But it's been 4 years since the divorce, and although he wasn't particularly looking forward to working with Addison again, the clinical trial and all of its career-boosting benefits were enough for him to decide he could overlook their history and work together.

To be honest, he wasn't surprised. He would concede even in his most bitter moments that Addison was an amazing doctor, an excellent doctor, the best in her field. Of course the trial only had room for the best. He and Addison—they had spent hours and years building their careers, mammoths in the medical field now, side by side, to the detriment of their marriage, he could say now. But there was no use rehashing that. He had moved on, he was with Meredith (post-it married—as little fuss as possible the second time around), and Addison was... doing whatever it was she wanted to. Last he heard, she had left New York, left Mark, and settled somewhere warmer. He didn't pay particular attention to anything Nancy ever mentioned about Addison and his ex-best friend. There was a chance he hadn't forgiven her completely. Okay, there wasn't just a chance. He hadn't, with certainty. But he could be professional, civil, even friendly if he really wanted to. It was gonna be fine.

Those were Derek's thoughts as he boarded a cab from Dulles Airport to GWU on a bright spring morning, commencing a year-long work arrangement that would make him see his ex-wife more often than he was really comfortable with. But it would be fine, he assured himself.

...

When Addison was offered to co-lead the clinical trial, she was flattered. Dr. Andrew Crow, one of her residents as an intern and now the liaison of the Kennedy Foundation, had sought her out specifically for her flawless track record. She would take monthly trips from California to DC, and then perform back to back surgery with none other than her ex-husband, Derek Shepherd.

She wanted nothing to do with Derek. The divorce still hung heavily and without closure over her head, and if she was being honest, she wasn't over him. What she did was inexcusable and unforgivable, and Derek had decided it just wasn't worth salvaging their 11-year marriage for. So while that decision hurt her beyond measure, she accepted it. She packed him up into a tiny box in the back of her head to help her get out of bed each morning and to keep her from reaching for a bottle of wine each night. She had packed him up, stapled and taped and wrapped the box shut, and moved on with her life. Or at least tried to. She was all LA now—zen, surfing, aromatherapy candles, yoga, and green juice. And dating. Well, trying to date at least. It was currently a messy single life, but she had moved on to some measure, and she figured she wasn't a Forbes Montgomery for nothing. She could work with Derek.

So when she decided to accept the position of co-lead, she was nothing short of of determined and confident. She was certain she could be professional, perform flawlessly at work, and lead such a prestigious trial to success. Addison Forbes Montgomery was many things, not the least of which was an excellent physician. She could keep her personal life out of work, at least if you don't ask any of the people she currently worked with in LA.

Those were her thoughts as she zipped up her pencil skirt and slipped on her stilettos. She assessed herself in the mirror, nodding to herself in approval. She was a perfect mix of LA and New York in the spring now—tanned legs, white pencil skirt, pale yellow top, and a low bun that made her impeccable jaw line look irresistible. She looked exceptional.

And things would be fine. They would.

She gathered her light coat and her purse and started walking from her hotel to GWU to meet Andrew. Things would be fine.

...

"You look great, Addison," Andrew greeted her warmly, arms wide open to embrace his old student. They worked together when she was an intern at Mt. Sinai. He and Richard Webber were good friends, and they mentored both her and Derek simultaneously through their internship.

Addison accepted the embrace, feeling even more confident that she made the right decision. "You too, Andrew. I can't believe it's been so long."

"Too long," he commented, resting a hand on the small of Addison's back to lead her to the conference room. "How is LA treating you?"

Addison hummed thoughtfully. "LA is great. Lots of sun. I live by the beach."

"You do?" he asked, a little surprised. "Never pictured you to ever leave the big city, to be honest."

"Yeah, me neither," she agreed as he ushered her into the conference room. "But LA has been good to me."

"I'm glad to hear it," Andrew smiled, pulling a chair out for Addison. She beamed gratefully and took her seat while he walked to the corner of the room where a coffee machine was blessedly brewing. Andrew fixed them both a cup of coffee before seating himself next to Addison. "We're just going to wait for Derek before we begin," he said. "His plane touched down over an hour ago, and he should be on his way."

Addison nodded, feeling just a little nervous about seeing Derek again after so long.

"Are you sure it's okay for you and Derek to be working together?" Andrew asked tentatively. "I'm thrilled you agreed to take this position, but I wasn't sure you'd be thrilled about working with Derek."

Everyone knew that Derek and Addison Shepherd, well, former Addison Shepherd, once the golden couple of Mt. Sinai, had split up after an indiscretion on her part. To people like Andrew, it came as a surprise. He had seen them through their earlier years as physicians and thought they were meant for each other. But to people who had worked with them in the final years of their marriage, it came as no surprise. The cracks in their marriage started to show, with Derek taking more and more surgeries he could have passed off to other doctors, and shoving Mark in his place for anything that involved his wife. They saw how Addison desperately tried to keep their marriage intact, planning dinners and dates and movie nights, but always ending up aching more than ever because he never showed. So really, when news of Addison sleeping with Mark made rounds, no one within the hospital was shocked. They knew it was all a matter of time. But the news shocked Andrew, who had really thought Derek and Addison could make it through anything.

"It's been four years," she answered simply. "You know what they say about time."

He nodded in concession. "Yes, but, you're sure?"

"I'm sure," she smiled in assurance.

"Okay, because I just wanted to make clear that you're my first choice. If you don't want to work with him, I'll find another neurosurgeon to take his place. Because if I had to choose between you and him, I'm choosing you," Andrew answered good-naturedly. "You're my star," he added with a wink.

Addison rolled her eyes at that. "We were all your stars."

"Nope, you were my star. And Richard's too."

"Well, I appreciate that," Addison answered with a smile. "But really, it's not a big deal. Derek's an amazing doctor, and he deserves to co-lead just as much as I do."

"Glad to hear it," Andrew said, the relief evident in his voice. But before he could say any more, there was a knock on the door, followed by Andrew's secretary's head poking through.

"Dr. Crow? Dr. Shepherd is here."

"Great, let him in," Andrew said as he stood up.

The door opened wider, and then Derek was in full view. He was dressed in a khaki suit that Addison was sure she had bought for him at some point, a light tie, and dark hair longer than she remembered. He looked just a bit older but still handsome as ever.

"Andrew," Derek greeted, taking the hand the older man offered and shaking it.

"Good to see you Derek. So glad you could make it out here."

"Wouldn't pass this up for anything," he said pointedly, before his gaze landed on Addison.

She stood up then and offered him and tentative, very professional, smile. "Dr. Shepherd."

He nodded, "Dr. Montgomery," he replied, flashing her his signature McDreamy smile that Addison thought looked nothing like the old Derek did.

She moved to give him a perfunctory half hug, (which is what ex-spouses did after a divorce, right?) and he surprised her by leaning in and accepting it. The touch brought a slight shiver to Addison, but she shoved it aside.

"Take a seat," Andrew instructed, and both younger doctors followed. "Well I'm glad to have you both here," he said. "It's been so long since I've seen the two of you, and now you're amazing surgeons. I feel exceptionally old."

Derek chuckled as he took a seat in front of Andrew. "Yeah, last time you saw us we were still fighting over appendectomies."

"We didn't know the business end of a scalpel."

"True," Andrew said. "And now you're both too good for an appendectomy. And you definitely know the business end of a scalpel." Then he pulled out a folder from his briefcase, opening it and handing them each a stack of papers. "So, let's get down to business shall we, before I give you guys a tour of the facilities."

Addison glanced down at the papers before her as she instinctively pulled a pen out of her purse.

"So, these are your contracts," Andrew continued. "You're both to be here for two weeks each month, starting this month, for a year. After this year, the rest of the work can be done online, and we don't have to meet in person as often anymore as we wrap up the data. You'll be supervising our surgeons at the hospital and also be performing your own surgeries. You get surgical privileges at the GWU Hospital. The foundation pays for your airfare and lodging, and all other incidental expenses when you guys are over here."

"Do we need to be here for the same two weeks?" Derek interjected, eyes not lifting from the contract he was scanning. Addison had to suppress an eye roll at that. She expected Derek to want nothing to do with Addison, and imply that they work the two weeks separately. Well, at least that's what Addison thought. Being married to someone for 11 years, and knowing precisely how petty Derek could be, Addison was almost certain that was the reason behind the question.

"You do," Andrew answered swiftly. Addison caught the slight downturn of Derek's lip, but said nothing. "You will be performing surgeries together, that's stipulated in section 3b of your contract. As co-leads, you will be in ORs together, not just as part of the trial, but also as a teaching experience for our young doctors. As you know, GWU is a teaching hospital so we'd like to make the most out of the presence of two very talented surgeons."

Derek nodded, turning the page of the contract.

"As you both may also know," Andrew continued. "This is a very prestigious grant, a once in a lifetime opportunity. For both of you. When they asked me to pick out the two people who would be leading this clinical trial, I immediately thought of the two of you." He cleared his throat then, causing both Addison and Derek to look up at him. "I understand that you have history," he said delicately, "but I need you both to understand how big this is and how we cannot let our personal lives interfere with work."

"I understand," Addison answered confidently. "Dr. Shepherd and I will be professional."

"It won't be a problem," Derek smiled reassuringly. "Dr. Montgomery and I will be on our best behavior."

"Excellent," Andrew answered dryly. Knowing these two for as long as he had, he knew there was bound to be trouble at some point. He was doubtful that their reassurances would hold, but he knew at least Addison would try. Addison was clearly his favorite, and for good reason. "I know you haven't operated together in so long, but honestly I look forward to watching what you guys can do in the OR."

Addison nodded. They used to be a symphony, she and Derek. In the OR, they moved together so smoothly, well-orchestrated and well-oiled. She wondered if they would still work as smoothly now.

Derek glanced over at Addison then. He was thinking the same thing.

"All right, how about I give you guys a tour of the premises?"

...

Two hours later, Addison and Derek found themselves in the lobby of the hospital, where Andrew had dropped them off after the tour with strict instructions to be there first thing the next day to go over the trial protocol with the rest of the attendings.

"So," Addison started, shifting uneasily but trying desperately not to show it. "Where are you staying?"

"The Marriott," was Derek's clipped reply.

Addison nodded. "Me too. Would you like to walk back together?" She hated how hesitant her voice sounded, a subtle thing that was obvious only to her, really.

"I'd rather not," Derek answered, and Addison grimaced. "Let's get a few things straight here, Dr. Montgomery," he said, looking squarely at Addison. "You and I aren't friends. We work together and that's it. I'd prefer if we don't speak to each other outside of work."

Addison's jaw dropped open before she shut it again, stunned by how forward Derek was. And also maybe a little hurt.

"I know it's been four years since the divorce. And while I've moved on, I also don't feel the need to socialize with you any more than I have to," Derek continued. "You can... go off and screw whoever you want, and I don't have to know about it, because we're just co-workers and nothing more."

If Addison was shocked by Derek's blasé words, she was even more shocked by his audacity, and how little he clearly regarded Addison outside of work.

"Screw you Derek," Addison huffed angrily before stalking out of the hospital.

So much for being professional.

...

"The target population for this trial are fetuses whose congenital anomaly scans show the presence of a myelomeningocoele. We screen them for the inclusion criteria. If they make it, they will then be randomized into two treatment groups: fetal repair and post-natal repair," Dr. Peter Smith, the pediatric surgeon on board, droned.

"Those randomized into fetal repair will undergo in-utero correction at 28 to 30 weeks age of gestation, where Dr. Montgomery and Dr. Shepherd will come in," he continued. "Those randomized into the post-natal repair group will undergo surgery as soon as possible after delivery."

"How soon?" Andrew asked.

"Usually within 48 hours," Dr. Smith replied.

Andrew nodded. "Addison, are you comfortable with this protocol?"

"I think we can go a little earlier," she replied, finding herself in the conference room the very next morning, dressed impeccably yet again and pointedly ignoring Derek who sat next to her. "Previous studies have shown we can do the surgery between 19 and 25 weeks, and then deliver via C-section at 37 weeks."

"Is that viable?"

Addison shrugged. "The risk for preterm delivery is still there, but between Dr. Shepherd and I, I think we can manage."

"She's right," Derek supplied. "The longer we wait, the more neurological damage can occur in utero. Amniotic fluid toxicity and further injury from trauma while still in the womb can happen later as the baby grows. The earlier the repair, the better."

Andrew nodded. "And the technique?"

"We standardize and perform a maternal laparotomy and stapled hysterotomy," Addison answered.

"And a layered neurosurgical repair postnatally," Dr. Smith added. Dr. Smith was good looking, Addison noted. He had brown hair and an angelic face, and spoke confidently but gently. By Addison's estimate, he was about her age, accomplished, intelligent, and driven.

"We follow up the patients for two years thereafter," Andrew continued, "and assess for outcomes."

"Independent walking, shunt placement, hindbrain herniation," Derek added.

"Good," Andrew answered. "Does anyone have any questions?"

A series of no's went across the table. Dr. Smith smiled at Addison, and she smiled back. Derek noticed and rolled his eyes at that but chose to say nothing.

"All right, if there aren't any questions, we'll make a line list of patients we've already seen at the hospital who fit into the criteria. We can start screening by the end of this week, and if we're lucky, we can start operating by next week."

When the meeting adjourned, Addison stood up to collect her things while downing the last of her coffee.

"I look forward to working with you Dr. Montgomery," Peter said, sidling up next to Addison as everyone started dispersing. Derek did roll his eyes at that, unable to contain himself.

"Oh please, call me Addison," she replied, flashing him a congenial smile. "And I look forward to working with you, too. I read the paper you published on diaphragmatic hernia repairs and thought it was excellent."

"Thank you," he replied, his smile soft, eye crinkling with sincerity. "Your article on partial molar excision was in the New England Journal of Medicine just last month. I'm impressed."

"That was nothing," Addison answered humbly.

Peter shook his head, "I can assure you that was not nothing. I can't wait to see you in action," he said, flashing her another big grin before showing himself out of the conference room.

Addison watched his retreating form before turning to Derek just as he gave a loud snort.

"Way to go Addison."

She rolled her eyes, "Now, I'm Addison?" she answered angrily, picking up her purse and her manila envelope. Only yesterday he insisted on calling her Dr. Montgomery, but leave it to Derek for her to conveniently and vehemently suddenly become Addison when there were other men involved. She hated the way he said her name, through gritted teeth, with so much disdain. From his mouth, her name sounded dirty, accusing.

"I can't wait to see you in action," Derek mocked. "Will you be dating everyone we work with, or only the ones who are just here?"

"Not that it's any of your business, Dr. Shepherd," Addison replied angrily, inundating his name with venom while throwing her lab coat over her right arm and walking to the exit.

Derek followed, hot on her heels. He didn't understand why he was no affected, or why he was riled up. But he supposed he just wasn't over the whole cheating thing, and it was bubbling from his chest, ugly and uncalled for. "So just the ones who are just here, right Dr. Montgomery?" he sneered.

Addison walked faster, not appreciating Derek's attitude. She knew those words, knew where he had picked it up. And she had to admit that it still stung. "I thought you didn't want to socialize any more than you have to outside of work?" she threw at him, exasperated.

"This is still work. And I deserve to know if this trial will be affected in any way by personal matters."

She rolled her eyes again at that, "Oh, just like this isn't personal, right Dr. Shepherd?" She stopped walking and turned to him. "Leave me alone Derek. You were excellent at that in New York," she said, giving him one last hard, meaningful look before walking away and jumping into the elevators just as they started closing.

...

Addison dropped her purse and kicked off her shoes unceremoniously when she arrived at her hotel room. Derek Shepherd was infuriating. They've only had two encounters, and he had managed to rile her up on both with nothing but a few choice words.

She didn't understand. If it was just her, she could put on a friendly facade and act completely civil. But Derek had to be the ass who couldn't let go of the past.

She growled in frustration as she pulled out a bottle of champagne from the fridge. It was only 11am, but she poured herself a glass anyway and plopped down on the couch. There were cherry blossoms blooming in the city, but all she cared about was drowning in a few glasses of hotel champagne to forget just how much her ex-husband still managed to affect her. How was she going to manage the next year with Derek being this way?

Pulling out her phone, she dialed Naomi's number, not caring that it was 8am in LA and she was probably busy getting ready for her day.

"Addison"

"Nae," she answered after taking a large gulp of her champagne. "I'm sorry, I know it's early."

"What did he do?"

Addison suppressed a sigh. "Being the usual ass that he is."

"Why am I not even surprised?"

"He has made an issue of me talking to a colleague, and asked me if I liked to screw men who were just there," she said, unable to hide the hurt in her voice. Those two words sent flashbacks of that fateful night in New York, sobbing and apologizing and begging, trying to explain that Mark was just here. Derek knew where it hurt the most and he used it to his advantage.

"Oh honey," Naomi said sympathetically. "I'm sorry."

"He told me yesterday not to talk to him outside of work, and here he comes rubbing the affair in my face all over again as if it hasn't been four years."

"You don't deserve that."

"I don't," she replied haughtily. "I gave him what he wanted. I got out of his hair. I've done my penance. I will not be reduced to the adulterous whore yet again."

"Then don't," Naomi said simply. "You've moved on. He's moved on. Just... you know... be the bigger person. Derek is acting like an immature, petulant child, and you better not be stooping down to his level."

Addison sighed at that, furrowing her brow and crossing her legs in the most unladylike fashion, Bizzy would be mad. "You're right. I guess I just didn't expect that he'd be so childish after all these years."

Naomi chuckled. "Addison, you forget who you're talking about. Pretty sure Derek Shepherd has always been just this side of petty."

"He has," Addison agreed. "I guess being the only boy of 4 girls does that to you. But I don't know. I probably just bring out the worst in him."

"And he's bringing out the worst in you," she pointed. "Don't let him."

Addison heaved another sigh at that. "Thanks, Nae."

"Remember," Naomi said. "You've moved on."

"Yeah," she agreed halfheartedly.

"Anyway, I gotta go. I'm dropping Maya off at school and we're running late."

"Thanks for picking up."

"No problem. Call me anytime if you need to talk."

Addison shut her phone with a click. She was a Forbes Montgomery, damn it. She didn't need to take this crap.

...

Derek didn't know what possessed him to be so... possessive. And petty. And so mind-blowingly childish. But he couldn't help it. All the determination he had to be civil and yeah, even friendly, just went flying out the window at the sight of Addison.

She was exactly the same, but not quite. She was still so gorgeous, well-dressed, and confident. But having been married to someone for 11 years, you notice the small differences too. She's confident, but she's a tad bit nervous and careful around him. She thinks it doesn't show, but he knows her too well, still, even after 4 years.

She wore the exact same perfume, styled her hair the exact same way. Even wore the same ridiculous expensive heels as she did in New York. But Derek could see she had been broken and put back together. A divorce would do that to you. Losing the love of your life would do that to you. He saw the cracks, and somehow that infuriated him. Addison shouldn't get to be broken. She had broken their marriage, not him. She had broken their wedding vows, not him. She shouldn't get to pick herself up, stand tall, confident and beautiful and outstanding as ever, as if she had not been the personification of the devil himself.

He sighed as he toed his shoes off and sat on the two-seater couch in his hotel room. He had walked a little slower back to the hotel, still reeling from a combination of jet lag and frustration. He knew Addison must be at her hotel room doing the exact same thing, pulling out a bottle of something to ease the pain.

Derek poured himself a glass of scotch. Just one for this morning, thank you very much. He didn't need to get plastered. He just really needed some help. He hated how much he still knew about Addison, could picture her clearly on her hotel's couch, stilettos off and legs tucked unceremoniously beneath her, nursing a glass of champagne. She could be calling someone now. Maybe Savvy. Maybe Archer. Maybe even Mark. He'd pay to not know her so well even after 4 years of divorce. He'd pay so much not to be able to recognize all the subtle things she thought he didn't notice anymore—the slight turn of the corner of her lips to indicate she was sad, the small flinch of her cheek before she schooled her face to hide that she was hurt, the way her eyes seemed to change in brightness when she was feeling emotional, and how they turned hard when she was putting on false bravado.

Just this morning, he had noticed so many of those subtleties. He was so angry—at himself for noticing, at Addison for existing, at Addison for cheating on him, at Addison for bringing out the worst in him. He realized then how much power they still had over each other. How his words could cut through her but she would try desperately for it not to show. How her actions, her mere presence made him want to kiss her and hate her all the same time. He hated how other men showed interest, and how she reciprocated mildly, and how he let the green monster hit her right where it hurt. He went for the jugular with that line.

It was one time.

He was just here.

I look at you and I feel nauseous.

Derek knew he had no right feeling so sucker punched at the memory, not after he had used it to purposely hurt her. But he still felt so unimaginably emotional thinking about that night.

His phone rang then, startling him out of his thoughts.

"Meredith," he greeted, sounding curiously out of breath.

"Hey," she answered said sweetly. "I'm in between surgeries, but I thought I'd just check up on you."

"I'm good," he answered, rubbing his temples a little. "We just reviewed the protocol this morning and I'm a bit beat."

She hummed sympathetically. "Jet lag?"

"I'd rather be cutting," he admitted dryly.

"How'd it go with Addison?" she asked, no hint of anything but curiosity in her voice.

Derek felt small tendrils of shame course through him as he recalled how had treated her the past two days, but tamped the shame down. "It was good," he answered casually.

"How is she?"

If the question surprised him, he didn't show it. "She's good. Tanner than I remember. But she looks like the same Addison to me."

He heard Meredith chuckle from the other end of the line. "That's good to hear. I hope it's not too hard for you to play nice."

Derek shook his head at that, a small smile gracing his lips. "Ah, well."

"Play nice, Derek," Meredith reminded him. "This is a big thing. I heard Dr. Webber talking about the trial and how your boss in DC is an old friend."

"Yeah, Andrew Crow and the chief were our residents when we were interns."

"The chief gives the impression that Addison was very in demand for this trial."

"I'm not surprised," Derek answered truthfully, taking a sip of his scotch even as he felt the beginnings of a headache coming through. "Addison is a great doctor," he said, repeating his thoughts from earlier.

"Addison is Richard's star."

Derek snorted. "Addison is everyone's star," he answered, a tinge of bitterness in his tone. "No one can ever measure up. She was the first to do everything. First appendectomy, first solo surgery, first choice for everything."

"Yes, well. You were chosen for this trial too, so you have to give yourself some credit for that."

"I'm not insecure," Derek said defensively. "It's fine really, Addison is great at what she does. I can give her that. It's just... being in the same room as Addison after so long... that's what's getting to me."

"Is she trying anything?" Meredith asked suspiciously.

"No," Derek answered quickly. "She's not. It's just her presence. Something about it riles me up," he said honestly. It was so easy to talk to Meredith. She was dark and twisty and sometimes hard to keep up with, but she listened and she listened well.

"I think you just need to take a step back from all of your emotions. You said it yourself, Addison is a great doctor. And I've heard from Richard she's moved to LA and made a life for herself there. Maybe if you just take a step back, it'll be fine," she offered.

"You've being very mature about this," Derek observed, and he could picture Meredith shrugging from the other end of the line. Not that he thought Meredith was immature. Meredith was actually one of the kindest souls he's met—never judging, always so trusting.

"It's been four years," she reminded. "You're over her. You don't need to feel so many things all at once. You just need to be professional. Maybe even try to be friends. Or friendly, at least. You've moved on, right?" she asked, no hint of insecurity in her tone.

"Right," Derek answered blandly.

"See? Good. Anyway, I have to go. I'm scrubbing in to a laminectomy in a few minutes and I still have to do pre-op," she said hurriedly. "But I really hope things turn out better, Der."

"Thanks honey."

"You're welcome. Have a good day. Love you."

"Love you," he answered before he heard the phone click from the other end.

He laid his phone on the side table, downed the rest of his scotch and then splayed out. What the fuck was even happening? Meredith had so much faith in him. She was sweet, so trusting, if a little naive.

As far as he was concerned, he hated her, hated what she did, and could never associate the word love with her again. He had no feelings whatsoever. And Meredith, sweet Meredith, banking on the last four years they were together, was entirely convinced it was just jitters, jet lag, that was making him less than dreamy than he usually was.

There were so many moments in the past that the very thought of Addison put him in such a sour mood. He was profoundly hurt by what she did, so immensely betrayed. He never thought she could do such a thing, and it broke him in ways he didn't know was possible when she slept with Mark, his brother for all intents and purposes. That night, when he told her he felt nauseous just looking at her, it was true. And for many nights after that, he felt nauseous just thinking about her. He hated her, hated what she did, hated how she ruined everything that was good in his life. She had ruined every good memory he had—of New York, of Mt. Sinai, of morning coffee, of walks in the park, of Christmas, of Italian paisleys and brownstones and kisses between surgeries. Everything he loved was tied to her, and they had all fallen to pieces after she broke him. The more immature side of him wanted to hurt her back. He never got his revenge, never got to hurt her the way she had hurt him. A shameful part of him wanted her to suffer, even though he was almost certain Addison was punishing herself enough as it was. He knew her so well, knew how self-deprecating and self-loathing she could be. She would hurt herself more than she had to. And he was sure she blamed herself entirely for what happened. He blamed her too.

Even now, years since separating from her, the thought of her sometimes made him physically uncomfortable. She sprung in his head less and less over the years, but when she did, every good memory there ever was was marred with darkness. He hadn't forgiven her. And allowing himself these moments to really think about how he felt for Addison, his heart contracted painfully, telling him just how raw and fresh the wounds still were if he thought about them hard enough. Which was why he couldn't help himself when he saw her and wanted to throw every small, petty, inconsequential thing in her face in a way he was never able to do before they divorced. He was well aware it was unfair, after all, he had Meredith now. But there was still so much pent up emotion that was making his chest burst at the seams and his vision just a little blurry that he couldn't help it if he tried.

Derek sighed. This wasn't him. This shouldn't be him, anyway. He chalked it all up to exhaustion and jet lag and the unexpected rush of emotions at seeing his ex-wife for the first time in four years. He decided tomorrow might be a better day, and closed his eyes for a cat nap.

...

Five days. Derek had been frighteningly civil for the past five days as they saw patients and screened them for surgery together. They hadn't operated yet. That would come next week. But Derek had been so professional, it scared her a little. She was waiting for the other shoe to drop—not that she would stoop down to his level if the other shoe did drop. She had vowed to herself she would be the expert that she was and ignore Derek's tantrums.

But he had been mercifully civil, and though Addison was on baited breath, she was thanking the gods that be that things weren't turning more sour than they initially were the first two days. Maybe the first two days was a fluke. They just got off the wrong footing, something about seeing other again for the first time since the divorce making them so emotional.

She and Derek were going to make rounds on a 23 year old patient pregnant with a baby with spina bifida. They were going to screen her, explain everything to her, and obtain her informed consent. They had done this together a couple of times before, and all times they were pretty successful. So all in all, Addison was confident things were going to go smoothly today.

They were standing next to the patient's bed, side by side, explaining to 23 year old Ashley Hammond that her baby had a spinal defect.

"Mrs. Hammond, your baby has a condition called spina bifida. It means part of his spine is growing outside of his body. This has been explained to you by the resident who assisted you earlier, correct?" Derek asked.

The patient nodded her head, apprehension evident on her face as she clutched at her growing belly. "We want the surgery before he's born," she answered, holding her husband with her other hand.

"May I know how many weeks gestation you're at now?" Derek asked mechanically, eyes drifting between the chart and the patient. Standard questions were standard questions.

Ashley paused for a while before she quietly answered. "24 weeks."

Derek nodded, his eyes scanning over the chart as Addison's eyes narrowed. She was looking at Ashley's belly, which seemed, in her experience, so much bigger than 24 weeks.

"When was the first day of your last menstruation, Mrs. Hammond?" Addison asked politely.

Ashley shifted uncomfortably. "Around September last year," she answered.

She paused. "Are you sure?" Addison asked slowly, suspiciously.

Derek turned sharply towards Addison when he heard her question. "Dr. Montgomery," he said with a click of the chart. "The patient says she's 24 weeks pregnant. It says so in the chart. You'd know that if you read it."

Addison rolled her eyes. "I know what the patient said, Dr. Shepherd, but how about you let me do my job? Or are you the OB GYN now?" she asked with irritation. She turned towards the resident and ordered her to wheel in an ultrasound machine.

Derek pulled Addison a little harshly by the elbow to the corner of the patient's room, Mr. and Mrs. Hammond glancing at each other uncomfortably. "Addison," he hissed. "What are you doing?"

"I'm checking gestational age," Addison answered matter-of-factly, unfazed by Derek's sudden agitation.

"The patient said she was 24 weeks. The chart says she's 24 weeks. I don't understand why you need to double check. They've screened her at the OPD. They've done an ultrasound. She fits the criteria, that's all we need to know."

"No, Derek," Addison whispered harshly, exasperated. "I've seen enough patients to know when they're lying."

Derek snorted at that. "Takes one to know one right?"

"Oh would you get over yourself," Addison answered angrily, pulling her arm which was still being held on tightly by Derek and walking over towards the patient.

"Mrs. Hammond—"

"Dr. Montgomery would like to apologize for the questions," Derek cut her off from behind her, fixing Addison a hard stare which warned her to drop it.

Addison rolled her eyes. "I just need to make sure. I know your chart says you're at 24 weeks, but I'm going to run an ultrasound anyway. As your OB GYN it's my job to make sure everything is as it should be. It's standard protocol," she said, almost daring Derek to disagree. "Are you absolutely certain your LMP was in September?" she asked, looking straight into Ashley's eyes.

She didn't understand why Derek was picking a fight, and in front of a patient at that. It was well within her bounds as the attending to check and double check before signing off on a procedure. Derek was just trying to push her buttons at every turn.

"Yes," Ashley answered, unable to meet Addison's gaze.

"Addison, what are you doing?" Derek asked through gritted teeth, his face so close to Addison's ear so only she could hear.

At that moment, the resident pulled in an ultrasound machine and Addison pointedly ignored Derek as she set up and poised herself to examine Ashely's belly.

"Dr. Montgomery," Derek warned, feeling incredibly frustrated. He shot the Hammonds an apologetic look. In his opinion, Addison was being exceptionally ridiculous. Clinical trial patients are screened tediously before they're even admitted. It was either Addison didn't trust the doctors who had assessed the patient before her (which was unprofessional and went against their code of ethics as physicians), or she just wanted to royally annoy him (which was also rather likely, because two could play a game).

"The gel will be cold," Addison warned perfunctorily as she squirted the gel on Ashley's belly and set the probe. Addison worked around the belly with the ultrasound probe, making measurements of the baby while the resident captured the images with the machine. She ignored Derek tapping his foot impatiently, and ignored Ashley and her husband looking at each other nervously.

"This is absolutely unnecessary. You're only doing this to annoy me," Derek whispered in her ear petulantly as he stepped closer to her.

"Not everything is about you," she whispered back, taking so much self-control not to kick Derek in the shin with her heels.

When Addison finished, she cleaned up the gel and then asked the resident to wheel the ultrasound machine out. Derek looked at her expectantly, arms crossed and waiting to hear her admit the patient was right all along. But he was out of luck.

"Mrs. Hammond, I'm going to have to ask you again," Addison asked, proud of herself for still sounding very patient. "When was your LMP? I need to know because we're planning to perform a procedure that is very time sensitive and potentially very dangerous, and it would be in your baby's best interest that you be truthful to us."

"Dr. Montgomery," Derek warned again, unable to comprehend why Addison felt the patients were lying. He turned to the parents and tried to muster an apologetic look. "Mr. and Mrs. Hammond, I'm truly sorry for Dr. Montgomery's forwardness. We're trying to do the best we can for the baby, and surgery now is the best."

Of course, the rational part of him knew it was Addison's medical license on the line if she signed off on a procedure without knowing all the details. But he wasn't very rational right now. He was just pissed and taking everything personally, which in retrospect was not very professional of him.

"No, it's not, Dr. Shepherd," Addison insisted, glaring at him. She turned to the parents again. "Ashley?" she asked pointedly, losing her patience.

Derek was fuming silently, eyes darting between Addison and Ashley. Why the fuck was Addison sabotaging a potential participant to the trial? Spina bifida isn't exactly rare, but it's also not the most common illness to discover. Every participant to the trial would count.

"Ashley," Addison repeated, looking between parents. When they avoided her gaze, she sighed as left with no choice, and then continued. "The baby looks much too big to be 24 weeks," she explained. "Late gestation ultrasounds aren't usually accurate to date the pregnancy, but your baby looks much bigger for someone who has had her LMP in September. I know from your chart you're not diabetic, so there's no reason your baby should be macrosomic at this stage in gestation."

There was silence for a few moments, and Derek resisted the urge to smack Addison's head with the chart. It was typical of Addison to make everything so goddamn complicated.

"I'm at 30 weeks," Ashley said finally, in a voice so small you had to strain to hear her.

"30 weeks," Derek repeated dumbly, nearly dropping the chart in surprise. Addison resisted the urge to shoot him a triumphant look, instead gestured for Ashley to continue.

Ashley tried not to cry. "We found out the baby had a spine defect about a month ago, and then we found out about this trial from all the research we did. We knew you would only operate until 24 weeks to qualify for the free surgery, and we really really want our baby to have the surgery," she said, her voice growing stronger as tears flowed freely from her eyes. "Please Dr. Montgomery. This is our only chance. We're too young and we don't have the money to pay for surgery, so we thought if we lied about how far along I was we could be considered and the baby could get the procedure he needs."

Addison sighed, shaking her. "I'm sorry, Mr. and Mrs. Hammond, but this is a risky thing you're doing. It's dangerous to lie to your physician, and dangerous for your baby as well. We can do the surgery, sure, but out of the trial. The trial only pays for those who fit the inclusion criteria. If you don't fit, it doesn't mean you can't get surgery, it just means you'll pay for it out of pocket and at your own risk." Addison paused, looking at the disappointed faces of the couple in front of her. Derek was silent for once since this all started. "The trial also covers for post-natal repair," Addison offered. "We have a surgeon on board who can do it after the baby is born. We can refer you to him, if you want."

"We want the surgery now," the husband said quietly. "We've been reading about it, and we think repairing the damage before he's born will give him a better shot." He paused and then looked pleadingly at Addison. "We just got out of college. We have student loans to pay. Our son is going to be born with god knows what deformities, and we're going to be paying for a hell of a lot of things after he's born. Therapy, specialized equipment, more surgery, child care, not to mention the emotional stress we already know this will bring. If we can minimize that in any way, we're willing to take the risk. Please. Dr. Montgomery," he pleaded. "Dr. Shepherd."

Derek looked sympathetically at the couple. He tried to put himself in their shoes. Caring for a child with spina bifida was taxing—financially, mentally, and emotionally. He's seen it in his patients' parents, their eyes tired, faces older than their real ages from having to care for someone who will need so much attention for the rest of their lives. His heart went out to them.

"Addison," he started. "Maybe we can..."

"We will refer you to Dr. Smith, our pediatric surgeon, for post-natal repair if you're serious about joining this trial," Addison said with finality, ignoring Derek, knowing exactly what he was about to say. "As much as I want to include you in this part of the trial, I can't. I'm truly sorry. This is mine and Dr. Shepherd's medical license on the line, and we can't risk that, especially if there are other options for the baby. This surgery is not the end all, be all. There are other options," she reiterated, trying to be comforting. "I'm really sorry," Addison said sincerely, pausing before she made a beeline for the exit.

Once in the hall, Addison walked and kept walking. She could hear footsteps following her, could hear Derek calling her name before she was abruptly pulled to the side towards an empty hallway.

"What?" Addison asked forcefully.

"What was that in there?" he said, gesturing emphatically.

"What was that in there?" Addison repeated incredulously. "You were trying to play hero. You were trying to give these people false hope, condoning them for lying, all after you undermined my authority and my expertise."

"Addison, I'm trying to do what's best for the patient."

"What's best for the patient? You and I agreed at the meeting that doing this surgery past 25 weeks is dangerous. How is that the best for the patient? I understand what you want to happen, Derek, but not at the expense of this trial. You were there when the protocol was set," she said sharply, upset at Derek for so many things that happened in the patient's room.

"I was, but unlike you, I actually have some compassion," he snorted.

"Compassion?" Addison repeated incredulously, her voice slowly growing louder. "This isn't about compassion Derek. If it were, of course I would do the surgery. But you questioned my authority, made it seem like I was wrong to double check how far along the patient. It was well within my bounds to do that. You even implied that I was irresponsible enough not to read the patient's chart before coming in. In case you've forgotten, Dr. Shepherd, I'm the OB GYN here, and I know what 24 weeks looks like," she huffed. "The patient lied, Derek. Patients lie all the time, and it is our duty to make sure we don't just take things at face value before we begin a procedure."

Derek snorted at that. "You would know about lying, Dr. Montgomery," he said before he could stop himself.

Addison huffed, all of a sudden so tired, the right draining out of her quickly. "This isn't about us, Derek." she said warningly, her voice low. "You can make all the quips you want about how I cheated, but that's between you and me. You want to keep throwing cheap shots at me, fine. But you do not get to do that in front of other people. And you do not get to do that in front of a patient." She stopped and shook her head. "This is not about us," she repeated, her voice hard. "You want to perform the surgery? Sure, be my guest. But not in this trial. You and I both know we can get de-funded for going against protocol. You wanna risk your medical license and put your ass on the line, go for it. But don't count me in."

She turned to walk away and then stopped, turning and fixing Derek another stern look. "Don't you ever slight my authority again, Dr. Shepherd. Especially not in front of a patient. Stick to your own lane," she said dangerously calm before finally walking away from Derek.

...

After that argument in the hallway, Derek and Addison blessedly had two weeks off from each other. They each flew out to their separate homes, exhausted not just from picking up the trial, but from dealing with each other. It took so much strength for Addison to constantly ignore Derek's offhand remarks about their history, and it took so much effort for Derek to remain civil with Addison despite all the unresolved emotions he had about her affair.

After the incident with Mr. and Mrs. Hammond, Addison pointedly ignored Derek in the hallway and at meetings, and spoke to him only about patients. She held her head up, kept her back straight, and went on with her work with confidence. There was no reason in the world she couldn't be the world-renowned surgeon she was, even with an ex-husband as petty as Derek fucking Shepherd. It was an art, really, and she had to ironically thank Bizzy Forbes Montgomery for giving her half a heart of steel so she could function without 1) wanting to scratch Derek's eyes out and 2) wanting to wallow in self-pity about how she was still (probably) in love with her ex-husband who apparently still hated her guts.

Derek, on the other hand, was only slightly shameful. He stopped questioning her authority in front of patients, but he couldn't help making snide remarks in Addison's ear whenever he caught her having a conversation with Dr. Peter Smith. That Smith guy annoyed him to hell, but he didn't bother dissecting why. He wasn't sure he was ready for the answer to that. So when their first two weeks ended, he looked forward to the blessed relief of being home with Meredith, even missed putting his waxed earplugs on before bed to deal with all the snoring. There was no Addison in Seattle. She didn't stay there long enough to infiltrate any of its corners with memories of her, not like New York. And not like DC now. He was glad to be home.

But after two weeks off, both he and Addison found themselves in the scrub room for their first OR together. Today would be the first time. Addison knew there would be people watching from the gallery, and she hoped to God Derek would behave for the audience she knew they were going to have. News about the trial's first surgery made its rounds, and Addison could swear as she scrubbed in that the gallery was standing room only. Front and center was Andrew, of course, who wanted to witness them in action for the first time in years. Beside him, Dr. Peter Smith, who looked pretty cute with is dark rimmed glasses.

"Did you get your coffee before surgery?" Derek asked pleasantly as he scrubbed his hands.

Addison was slightly taken aback by the... was that kindness in his voice? "Yes, thank you," she answered politely, rubbing the soap between her fingers. "I hope you did too. I know the jet lag sucks," she said by way of small talk.

Derek turned his head slightly and gave a half smile. "The coffee at the hotel is crap," he admitted. Coffee was never bad in Seattle. It was one of the things he absolutely loved about the city.

Addison laughed, startled, but she agreed anyway. Was it possible that she and Derek were being, dare she say, amicable? It was starting off incredibly light, if a little forced, and if there was a way to keep things light until the end of the surgery, then she'd count herself lucky. She stepped back and pulled a paper towel out of the container.

"The coffee in Andrew's office is better. Pretty sure they're small lot Ethiopian beans."

"Or maybe a nice Colombian blend," Derek offered, mimicking Addison's actions with a paper towel. Derek couldn't see Addison's lips from behind her surgical mask, but her eyes crinkled, letting him know she had smiled. Somehow, surprisingly, that put Derek in a lighter mood.

They stared at each other for a moment after that, a mutual understanding of what this surgery meant for them. Their first time operating in tandem, no longer as Drs. Shepherd, but as Dr. Shepherd and Dr. Montgomery. Their names hadn't been on the board as A. Montgomery and D. Shepherd since internship, and the nostalgia was almost unbearable. Neither of them acknowledged it, but they both knew they were thinking about the same thing, realizing the significance of what they were about to do. Derek and Addison in the OR again, after more than 5 years. What a personal landmark. For a few moments, all of the negative history between them was set aside, cease fire, a truce of sorts.

"Good luck in there," Addison said finally, breathing a little heavily.

Derek smiled from under his mask. "It's a beautiful day to save lives, Addie," he answered seriously, staring intently into her eyes.

Addison paused, wistful for just a second as she heard those words, heard Derek call her by her nickname. She grinned widely. Derek grinned back before they both walked into the OR.

As expected, the surgery was a success. Derek and Addison moved in perfect synchrony, their hands moving expertly between each other's. Their ability to communicate with their eyes, with one word, with a look, with a quiet tsk or a pause, all seemed to return like muscle memory. In the few hours they were operating, they were Derek and Addison again, Drs. Shepherd, eyes transfixed on the OR field but somehow still acutely aware of what the other was doing, what the other needed. Some would argue it was something all doctors who operated together should have. But even the nurses who scrubbed in felt it was different. Addison and Derek, they were electric. Magnetic. A fantastic orchestra of fingers and glances, instruments, cutting, suturing, probes and scopes, "Addie"s and "Der"s. They were mesmerizing to watch, and the entire gallery remained entranced from start to end, a symphony between two doctors, art all on its own.

As Addison threw the last stitch to close up the patient's abdomen, excited murmurs erupted in the OR and in the gallery, and Andrew smiled proudly from where he sat.

"Amazing work Dr. Montgomery, Dr. Shepherd," Dr. Price, the anesthesiologist said.

"Thanks," they answered in unison, eyes meeting and then beaming, reeling from the excitement of their accomplishment. They removed their gowns and gloves, pulled their masks down, and walked back to the scrub room to wash their hands. But before they did, they instinctively pulled towards each other in a gentle, sincere half hug that felt like coming home.

"You did great Add," Derek said and then kissed the top of her head.

Addison strained her neck to kiss Derek's cheek, not caring about the propriety of it all. "You too."

They pulled away, still smiling and started scrubbing their hands clean.

"We still got it," Derek commented, immensely proud of the work they had done, but also sounding just a little surprised by the realization.

Addison laughed melodiously. She sounded happy for the first time in a while. "We still do."

Just then, the door to the scrub room burst open and Andrew barged in, grinning broadly, his excitement radiating, uncontained.

"You were gods today," he announced, standing between Addison and Derek and putting a hand around each of their shoulders. "You were gods today and will be gods for the rest of this trial. What a triumph!"

"It was routine," Addison said nonchalantly. Modesty wasn't exactly one of her best traits, but this was one surgery out of many more to come.

Andrew shook his head. "I can't wait to tell Richard. Our protégés all grown up." He looked between Addison and Derek, feeling vastly nostalgic at the collaboration he saw happen at the OR today. They had always worked so well together. Even for something as simple as suturing a laceration in the emergency room, they were always better together. And today, in the OR, operating on a fetus' back, he could see that years of working with each other had only served to sharpen their skills. They were incredible.

Derek finished washing his hands and pulled away from Andrew, taking a paper towel to dry off. "It was pretty textbook," he said. "But it was easy with a very skilled partner," he said generously.

Addison's eyes widened, not expecting the compliment. They had been at each other's throats for the past weeks that it was hard to conceive anything that sounded remotely nice from Derek. But this was their moment, and she allowed herself to revel in it.

"Yes," Addison agreed. "Glad to see you've only grown better through the years, Dr. Shepherd."

Derek beamed at that.

"Sounds like a new and improved version and DerekandAddison," Andrew commented, smiling knowingly between them.

"AddisonandDerek," she corrected instinctively, a habit she had from time immemorial. Rote, like many things in their marriage, and like many things that occurred in the OR today.

Derek rolled his eyes good-naturedly. "Derek and Addison," he said with finality, before accepting Andrew's offer for coffee at his office.

...

The high was short-lived. The next day, Addison found herself at the nurse's station, looking over the chart of the patient from the previous day. Dr. Smith had walked up to her, grinning broadly.

"I meant to congratulate you yesterday," he said as a way of greeting, standing next to her.

Addison looked up from the chart and smiled.

"I was in the gallery," he explained. "Your work was phenomenal. Dr. Shepherd too. I suppose you need delicate hands to be a neurosurgeon," he mused.

Addison chuckled. "You need delicate hands to be a surgeon, period," she said. "But thank you. Yesterday was a pretty good day. I hope the rest of the ORs run as smoothly."

"I honestly wouldn't count on it," he said, "as you know. But one can always hope. Besides, with you on the team, there are more chances of things going well than the opposite."

"I appreciate that," Addison said, tucking a stray strand of red hair behind her ear. Her hair was done in a half ponytail today, framing her features nicely in the way she knew Derek used to like. Not that she fixed her hair up for Derek or anything. She would deny it vehemently if anyone asked. "When do you get your first surgery?"

"I have one scheduled tomorrow morning, actually," he answered. "Mother delivered yesterday, so we're doing the correction at 48 hours of life."

Addison nodded. "If I don't have anything scheduled, maybe I'll come and watch."

"I would like that," he answered sincerely. "But how about you do me one better and take a walk with me this afternoon, if you don't have anything scheduled."

Addison raised a perfectly arched brow at that. "A walk," she repeated.

He nodded, unperturbed. "The cherry blossoms are in full bloom now. I figure we could take a walk around the Tidal Basin so you could see it. I assume you've never been."

"I've never been," Addison admitted. Well, she'd never seen the ones in DC anyway. "But you have?"

He nodded. "I took my premed in Georgetown, and every year I would go to see them. They don't last very long, and today might be the last day they'll be in full bloom. It's a tourist trap, really, but it's a beautiful sight and I think you might appreciate it."

Addison thought about it for a moment. "I do love flowering trees," she said slowly, mulling the the thought in her head. "And I haven't really seen much of DC since I arrived."

"So it's settled then?" he asked hopefully. He looked so adorable, almost like Addison wanted to hug him. He wasn't hot, not like Mark was, or even that cop she dated in LA for a while. In a lot of ways, he was like Derek. She wouldn't call Derek hot (unless they were in bed, where it was true no matter what). Derek was endearing. And there she was comparing every guy to Derek yet again.

Suppressing a sigh, Addison nodded and plastered a smile on her face. A little fun couldn't hurt. "Do I meet you at the lobby?"

Peter grinned at her reply. "Wear comfortable shoes," he reminded, before giving Addison one last look and walking away, a spring in his step.

Unbeknownst to Addison, Derek had seen the whole exchange as he was about to check the same chart Addison was currently holding. All the good vibes he had from yesterday's successful surgery went sour, and he was once again filled with annoyance. All the hostility he felt towards Addison suddenly came rushing back.

"Nice one, Addison," he commented sarcastically as he took the spot Peter had just vacated at the nurse's station. "Landing a date to see flowering trees."

Addison just gave him a look.

"Does he know you're allergic to pollen?"

Addison rolled her eyes. "I am not allergic to pollen," she retorted, her eyes going back to the patient's chart, to the CTG taken the night before.

"You are too," Derek insisted, not really understanding why he had to needle her that way. If she wanted to date, she was free to do so. But something in his chest made him feel so unpleasant at the thought.

"To cottonwood," Addison pointed. "I had that allergy test remember?"

Derek shrugged. "There can be cottonwood at the tidal basin."

"Don't act so concerned" she answered sarcastically, looking up from the chart. The nurses glanced up at the former Shepherds, eyes darting at the bantering they knew was about to ensue. "I can show up here edematous and anaphylactic and it still wouldn't matter to you. We aren't married."

Derek shrugged. "I'm not concerned. And yes, we aren't married. You've made it abundantly clear you're incapable of keeping wedding vows."

"Sublime," she retorted blandly, eyes back on the chart and choosing not to take Derek's bait. "Leave me alone Derek."

"I need that chart," he responded matter-of-factly.

"Then you'll have to wait for your turn," she said without looking up. "They teach you that in kindergarten, don't they?"

Derek scoffed. "They also teach you not to take things that aren't yours, but I guess Mark skipped class that day."

"Mark isn't here," Addison answered with fake serenity, offering him an overly friendly smile before rolling her eyes and looking back at the chart. "You can take it up with him when you see him."

"I don't plan on seeing him. I've seen way too much him than I'd like. I'm pretty sure the vision of his ass as he ran for the door is enough to last me a lifetime" Derek retorted. "In fact I didn't plan on seeing much of you either after the divorce. And yet here we are."

"How lovely," she said dryly. Exasperated, she looked squarely at Derek. "Look, how about I just page you when I'm done with the chart and you don't have to stay here and insult me the entire time?" she suggested impatiently.

Derek shrugged but stayed where he was. He was already there and there was nothing else to do that day.

There was a blissful few moments where neither of them said anything. And then,

"Peter doesn't know you hate cherry blossoms."

"Derek," Addison groaned in frustration. "Don't."

But Derek was persistent. "The Captain brought you to Roosevelt Island when you were 12 for Cherry Blossom Festival—"

"Yes and he ended up screwing Jennifer, my nanny, in the truck while he sent me to buy myself some cotton candy. Thank you, Derek, for that reminder," she finished bitingly. "And before you say it, yes, screwing around apparently runs in the family. I am a Montgomery after all," she glared.

"I wasn't—"

"You were going there," Addison said, as if daring him to say otherwise. "But now that we've established that, can you just go and be an asshole somewhere else so I can finish my job and enjoy the cherry blossoms with Peter?"

Derek sighed and walked away, berating himself inwardly for not having the self-control to act as mature as he said he was going to.

...

Two days after the cherry blossom thing (an excursion which didn't push through because Peter was paged for an emergency, much to Derek's gloating), Addison and Derek once again found themselves in the OR, operating on a 31 year old mother who was 24 weeks pregnant.

"Dr. Patterson," Addison said, addressing the intern as she dissected the abdomen carefully. "What supplement is lacking in fetuses with neural tube defects?" she questioned.

"Folic acid," the intern, a male who Derek thought seemed an awful lot like Alex Karev answered Addison a little gruffly. He looked like he wasn't sure he wanted to be there. This was an OB case after all, but a very prestigious one as part of the trial. Derek narrowed his eyes at him.

"How much folic acid should a woman be supplemented with during pregnancy?" Addison continued quizzing, still working on the patient intently.

The intern, who wasn't really getting in on the action but instead had to answer all of Dr. Montgomery's questions, looked annoyed.

When he didn't answer, Addison glanced at him quickly. "I asked you a question, Dr. Patterson," she said with command. Addison was always known to be tough on her students, but only because she wanted them to learn.

"Um," the intern answered, thinking for a moment. "400 mcg per day starting before pregnancy."

"Do you give the same amount if the mother has had a prior pregnancy with a neural tube defect?" Addison continued.

Dr. Patterson rolled his eyes, unable to hide that he did not appreciate Dr. Montgomery quizzing him. "Look, Dr. Montgomery. I'm here to cut, not to get asked a bunch of questions," he said boldly.

Derek cringed on his behalf as he noticed the subtle change in Addison's eyes when she was about to berate a junior for insubordination.

"Wrong, Dr. Patterson. You're here to learn. You don't get to hold a scalpel if you can't answer my questions," Addison replied harshly, unfazed. "How much folic acid should a mother receive if she has had a previous pregnancy with a neural tube defect?" she asked again, her voice hard. Derek knew this was going to be the intern's last chance.

When Dr. Patterson didn't answer, Addison rolled her eyes, annoyed. "Patterson, scrub out," she ordered. "And get me someone who's actually willing to learn," she continued, eyes not lifting from the surgical field but brows set in the way they did when she was trying to rein in her anger.

"Whatever, dude," Patterson replied, throwing his gloves and tearing his gown off unceremoniously. Everyone was quiet, not sure what was going to happen next. But before he left the OR, he turned and looked straight at Dr. Montgomery. "You act all high and mighty here in GWU Dr. Montgomery, even if this isn't your turf, but you don't know that everyone talks about you and Shepherd around here. You're always fighting, always arguing— can't even do it in private. If you hate each other's guts so much, why don't you just go at it with the scalpels you got there," he proclaimed arrogantly. For a moment there was nothing but the steady rhythm of the beeping monitors filling the room as everyone remained silent. Dt. Patterson scoffed then. "You pretend to be professionals, world-class surgeons where people from all over America come to you, but really you're just a bunch stupid, arguing kids yourselves," he said finished.

There was deathly silence, even Derek was stunned and a hell of a lot chagrined. The nurses exchanged glances, and even the anesthesiologist gawked at the intern's audacity. Everyone was waiting for Addison to yell, to berate, to say something, but instead, she looked up at him coolly and fixed him a hard stare. "Get out of my OR, Patterson. Don't make me say it again," Addison said frighteningly calm.

Patterson shook his head and left, leaving everyone stunned. Up in the gallery, people were whispering, no doubt already gossiping about how Patterson had royally pissed off Dr. Montgomery. In the OR though, there was tense silence as Addison continued her work. Derek said nothing, only watched her work and waited for his turn with the patient. He also felt immensely insulted and affronted by what Patterson had said, but he had the good sense not to add to the stress by reacting. Within a few minutes, another intern scrubbed in and stood beside Addison, shaking just slightly as she took her place.

"Good morning, Dr. Montgomery. I'm Dr. Hernandez. I'll be taking the place of Dr. Patterson today," she stuttered.

"Very well," Addison replied, not bothering to look up. "Stand here, please, Dr. Hernandez," she said, signaling for her to come closer. Without pause, Addison continued. "What is the difference between a meningocoele and a myelomeningocoele, Dr. Hernandez?"

The intern was shocked at how quickly she had been asked a question, but she recovered quickly and paused, her nervousness still very apparent. Derek swore he could see her starting to sweat under the OR lights. He felt a little bad for the intern. Addison didn't seem like she was in such a good mood. And after what Patterson had said before leaving the OR, it didn't seem like Addison would lighten up anytime soon and cut anyone any slack. This was typical. Bad mood Addison meant all the interns had to scramble and review their textbooks because she was sure to ask the hardest questions. If he wasn't still so offended by what Patterson had said, he would be amused.

"Um... Ma'am..."

"Dr. Hernandez," Addison said impatiently, her tone leaning on the intern's name in a way that conveyed she was expecting an answer soon.

"A meningocoele has no neural elements in the sac... Ma'am," she stammered, her voice shaking. "A myelomeningcoele has all 3 components—meninges, CSF and neural elements... Ma'am."

"Good," Addison replied, signaling for an orderly to push the ultrasound machine closer the field. "And how are those different from spina bifida occulta?" Addison asked.

Derek watched as Addison took the probe and maneuvered it to locate the fetal back. Addison loved to teach, and he used to love watching her impart all she knew to her students. She was the kind of person who never held back on any information she knew. She wanted her students to end up better than her, something she had learned from her own mentor, Vivian.

"Occulta means the defect is hidden under a layer of skin," the intern answered nervously, her voice unusually high pitched and her hands trembling. It was clear Patterson had told her about what happened and how Dr. Montgomery wouldn't let up on the questions.

"And does that cause disability, Dr. Hernandez?" Addison asked as she located the fetal back.

"S-s-sometimes, Ma'am, I mean, Dr. Montgomery, Ma'am." Dr. Hernandez took a calming breath and then, "A spina bifida occulta can occur in up to 20% of the general population, without symptoms, Ma'am."

Addison looked up, satisfied. "Very good, Dr. Hernandez." Addison turned to the scrub nurse.

Repeating her earlier question, Addison looked up to meet Dr. Hernandez's eyes. "If a mother has had a previous pregnancy with a neural tube defect, how much folic acid should she take for her next pregnancy?" she asked, eyes trained on the intern expectantly.

The intern bit her lip, shifting uneasily from her right foot to her left foot. "I'm not sure, Dr. Montgomery," she started. "But... I believe we increase the dose from 400mcg to 4g daily if with prior history," she answered apprehensively.

"Surgeons can never be unsure Dr. Hernandez," Addison said, face unreadable. "How much folic acid is given?" she repeated.

The intern took a steadying breath before answering in a voice she hoped sounded more confident. "4g daily, Ma'am."

Addison nodded, satisfied. She turned to the scrub nurse. "Please give Dr. Hernandez the probes. She can insert the ports into the uterus."

Dr. Hernandez gasped in surprised. "What?"

"Addison," Derek said warningly, himself surprised by the turn of events. He knew Addison was trying to teach but he didn't think he would let an intern perform such a delicate procedure. "Are you sure?" he asked, noting how the intern's hands were still trembling.

Addison looked at Derek squarely. "I'm sure."

"Addison," Derek said again. "The risk is high and –"

"I know, Dr. Shepherd," Addison replied, cutting him off, slowly becoming irritated with Derek.

"Dr. Montgomery, with all due respect, maybe Dr. Shepherd is right," Dr. Hernandez interjected. "I- I'm honored but—"

"No buts," Addison said. "Are you here to learn or not?"

"I'm here to learn Ma'am," the intern answered defensively.

"Then be here to learn," Addison said with finality. "Do you not trust me?" she asked, brow raised in challenge.

The intern's eyebrows shot up in surprise. "Of course not, Ma'am! It's just, I'm not sure I'm qualified—"

"Dr. Hernandez, you will not learn by simply watching. And you will certainly not learn by reciting answers you read from your textbooks. Surgeons learn by doing."

"Addison, this isn't a good idea," Derek warned. "She can puncture something and—"

"Are you questioning my authority in my OR, Dr. Shepherd?" Addison asked calmly, but her eyes ablaze with muted anger.

Derek steeled his face, his eyes also conveying his dismay. "This is my OR too, Dr. Montgomery. And my patient just as much as yours. And I don't think your intern is qualified to do such a procedure."

"She is not doing it alone, Dr. Shepherd. I'm right here to assist her," Addison glared. "Or are you going to imply that I am not qualified to teach, too?"

Derek and Addison stared at each other for long moments, the tension in the OR even thicker than when Patterson first left. The observers in the gallery were whispering, no doubt gossiping about how the former spouses were bickering yet again. By that point, and after all the bickering they had done both in and out of the OR, everyone on staff knew Dr. Montgomery and Dr. Shepherd didn't like each other very much. Or at all.

"Nurse Julie, kindly give Dr. Hernandez the probes," Addison said finally, in a way that left no question, not taking her eyes off of Derek's as the scrub nurse uncertainly handed the probes to the anxious intern.

"How many fetoscopic ports, Dr. Hernandez?" Addison asked, still not taking her eyes off Derek's angry ones. Everyone in the OR seemed to have baited breath. Derek knew this was a teaching hospital, and of course, of course he knew that to be a surgeon, you had to have some action. And he of all people knew Addison was an excellent teacher. But this just wasn't the time for these things, especially when the tension in the OR was already immensely palpable.

"Three, Ma'am," the intern answered.

"Show me where to insert them," Addison instructed.

Uncertainly, the intern moved forward and pointed to the three areas where the scopes were to be placed in relations to the fetal back. Addison nodded approvingly. Wordlessly, she guided the intern's hands to successfully insert all three scopes in the proper place, much to the relief of Dr. Hernandez, and everyone else in the operating room.

When the scopes were in place without a hitch, Addison looked up at Derek smugly. "All yours, Dr. Shepherd," she said with a flare, not bothering to catch Derek's reaction.

Despite the rough start, the surgery was a success. When it was over, the intern thanked Addison profusely for the opportunity to learn, rambling about how no one had ever trusted her enough to do something so delicate. In between her thanks, she rambled, "I don't care that they call you Dr. Petty and Dr. Pretty. I think you're both great surgeons, and I'm honored to have worked with you," she said. And then her eyes widened and her hand flew to her open mouth. "Oh my god, I'm so sorry. I shouldn't... I shouldn't have said... I'm going to go now," she said, flushed red from embarrassment. "Thank you so much Doctors," she managed, making a swift exit from the OR.

Addison sighed and took her gown and gloves off, tearing away her mask as she made her way to the scrub room. Derek was right behind her. They were both quiet as they washed their hands, both of them exhausted from everything that happened in the OR.

"I'm sorry," Derek said finally, his voice tired but sincere.

"Excuse me?" Addison asked, turning her head towards Derek.

Derek shook his head. "I did undermine your authority in there," he admitted, in a rare display of humility. "I know this is a teaching hospital. I know you're a good teacher. I shouldn't have questioned you in there when I knew you were going to guide that intern."

Addison sighed, shaking her head. "No, I guess you were right. We work as a team, we kind of check and balance each other."

Derek shook his head at that. "Even then, I shouldn't have done it that way. There was a better way to ask about it."

Addison stopped and turned to face Derek, her hip leaning on the metal sink of the scrub room. "I appreciate that."

Derek gave her a half smile. "Dr. Petty and Pretty, huh?"

Addison looked thoughtful for a moment. "We all know who Dr. Pretty is," she said with a pointed look at Derek. And then she rolled her eyes and announced, "It's pathetic."

"It's Pathetic," Derek corrected, emphasizing the word.

"It's like high school."

Derek agreed. "Pathetic" he repeated.

"I don't remember Mt. Sinai being this much of a gossip mill. But then again, we weren't really much of a hot story back there. Rupert and that nurse Evangeline were hot items for the longest time after they got caught having sex in the boiler room," she recalled with amusement. "But you and I... we weren't...I mean... not until the end," she finished sadly.

Derek nodded thoughtfully, schooling his face to avoid grimacing at the thought of the final year of their marriage. He was far too oblivious to what others were saying about them then, and after he left, he didn't exactly care what they said about Addison.

"No, I guess we weren't interesting enough in New York," he concluded. He paused, and then, "They call me McDreamy in Seattle," he announced. "The gossip mill churns like mad there."

Addison rolled her eyes and smacked him in the arm playfully. "You? Dreamy? That's disgusting. I hope that embarrasses you."

"It kind of does," he admitted, cheeks reddening because he knew that with Addison, or at least the old Addison, there was no pretense. She had seen him through his worst moments, the times when his past caught up with him and he was dark and difficult. There was no way Addison was going to fall for the whole dreamy thing, which really only proved how much he had changed, or how much he had tried to cover up his past.

The way they oscillated between okay and not okay, friends and enemies, team mates and then rivals, was dizzying. How could they work so wonderfully together one moment, and then hate each other's guts the next? It was tiring just to think about it.

At that, Derek gave her his best dreamy smile, winking at her salaciously before walking away. Addison only shook her head.

...

Four days later, Addison and Derek found themselves bickering at the nurse's station about how to manage one of their patients post-op. Addison wanted to discontinue IV fluids because the patient was feeding orally, but Derek insisted on keeping the line even at minimal rate. Later that day, they argued in the locker room about Addison planning a reschedule of her "date" with Peter, and Derek made yet another snide remark about Addison and her messy single life. Two days after that, Addison had promised a patient everything would be okay and that the surgery was pretty routine, to which Derek had argued that they weren't supposed to be promising anything to patients. And besides, what did Addison know about keeping promises if Addison had broken their wedding vows? That made Addison walk out of the conversation and not speak to Derek for the rest of the day. The nurses were gossiping, and they were nearly afraid to refer their concerns about patients because between Derek and Addison, there was always some form of heated argument going on. It came to a point that one of the younger nurses absolutely refused to talk to Dr. Shepherd about his patient's blood pressure as he sulked at the nurse's station, and the patient coded. She came through, but it only highlighted the fact that Addison and Derek's constant friction was alarming, affecting hospital staff and hospital operations.

The nurses one by one started complaining to Dr. Crawford. Even the residents came up to him to express their concern. Andrew couldn't even argue in their defense, because good as they were, seeing them bicker and make up so many times during the day was absolutely exhausting. He knew he had to talk to them.

He summoned them to his office one afternoon. Andrew could tell they were quarrelling underneath the harsh whispers they exchanged as they walked into his office. Andrew rolled his eyes, exasperated but not surprised.

"All right, that's enough," Andrew said, his voice louder than he had intended. "Are we professionals here or what?"

Addison and Derek both looked initially stunned, and then had the good sense to meekly look down. She stared at stilettos and Derek suddenly found the doted pattern of the carpet very interesting.

"Derek, Addison," Andrew sighed. "I have been getting numerous reports about the two of you, and not the kind you'd like to hear about."

"At least it's not about dirty things in the on call rooms, like in internship," Derek tried to joke. Addison grimaced, shaking her head, wanting to smack him in the head right there and then. How the hell could Derek joke about sex when it was clear they hated each other's guts? It was hot and cold with him all the freaking time.

"I didn't need that image in my head, but thank you for that, Derek," Andrew responded dryly. He knew of the one too many times that Addison and Derek were caught in not so decent positions in on call rooms and exam room and locker rooms all through their internship and residency. He caught them once or twice himself, and he really could have lived the rest of his life without the reminder.

"Sorry," Derek said sheepishly, training his eyes back on the carpet and avoiding Addison's death glare.

Andrew exhaled long and slow. "The two of you have got to work this out amongst yourselves. You have two weeks off where I hope you will think about how you're going to address this problem. You promised me your... history... wouldn't be an issue. But if you don't start playing nice, there will be consequences neither of us will be happy about."

"Yes, Sir," Addison answered.

"Take the two weeks. Refresh yourselves, recharge. Derek, go fishing. Addison, go to the spa. Do something. Anything. And then talk. I want you both to talk about this, communicate with each other, and come up with a plan for this."

"You sound like a marriage counselor," Derek said wryly.

"You wouldn't know what a marriage counselor would sound like, you didn't want to see one when we were married," Addison quipped bitterly, rolling her eyes. When Andrew gave her a pointed look, she just shrugged.

"Look, you two have a lot of unresolved issues. While I would like for them to be resolved, I know there's a lot that needs to be hashed out between you from ancient history, and I don't think you're ready for all of that. I don't think you even feel like it's necessary at this point, since you're divorced after all. But I ask you to please table your issues while the trial is ongoing. Do it for me, as a friend. But do it for yourselves too. Hate is a terrible feeling to harbor, and you're only punishing yourselves." Well, technically they were punishing the hospital, and the patients too, but he didn't need to elaborate that at this point.

Derek nodded slowly before turning his head to look at Addison. She turned her head carefully then and met Derek's eyes. They both looked so sad. There was so much history between them, and not all of them were bad. There were so many happy memories, too.

"Times weren't always bad between the two of you," Andrew reminded, more gently this time. "There were many, many blissful moments you shared together. And I'm not just talking about marriage. I'm talking about graduating from medical school together, finding your first apartment together, getting into internship together, getting into residency together—all of them, side by side. Don't let go of that. I'm not saying get back together, because that ship has obviously sailed. But you guys have had many happy times from which to pull from, so you can work together like the team I know you are."

"If you ever decide to quit surgery, you'd do well as a marriage counselor," Derek remarked dryly.

"I only do this for people I care about," Andrew answered pointedly.

After a moment's pause and quite a serving of remorse, Derek gingerly held his hand out to Addison, a sort of peace offering. Addison looked at the outstretched hand suspiciously before she took it tentatively. Their hands were warm, and still fit perfectly in each other's in a way that surprised them both. Derek squeezed it and gave her a reassuring smile. There were still so many things to work through, but there were also numerous parts of Derek and Addison, the good ones, that remained. It was a waste to let that all go.

...

When Addison arrived at her home in LA, she could admit she was dead tired. Not physically, because she flew first class and it wasn't a red eye flight. But mentally, emotionally? The roller coaster ride of her and Derek's relationship was a never-ending cycle of hate and disdain and tolerance, and sometimes even kindness. She wanted so badly to sort out her feelings for Derek, but that would mean opening a Pandora's box of emotions she wasn't sure she was ready for.

On the one hand, she knew she would always love him. Derek was huge part of her life, the person beside her through every important milestone of her career, who saved her in more ways than one, showed her what it meant to have a family, to have someone to come home at the end of a long day. There was a moment in time when Addison's life centered on only two things, her career and Derek. Nothing else mattered. And she loved him so blindly and completely and unequivocally that when he stopped noticing her, she felt lost. It was unlike her to trust so completely, not after the childhood she had. But Derek had given her the home she always wanted, and loved her in the ways she needed to be loved. In the end, it was stupid to give her all to Derek Shepherd.

She had hurt him so deeply when she slept with Mark, no matter the reasons behind the indiscretion. Nothing could justify it, and she would live with the regret for the rest of her life. But she had paid her dues, did her penance, prayed one million hail mary's even when she wasn't even remotely religious in an attempt to absolve herself of the biggest sin of her life. She realized only Derek could really absolve her of that. And he hadn't.

Reeling from the affair, when she moved to Seattle and Derek treated her like dirt under his shoe, Addison knew she deserved it. She deserved every name, deserved every quip, even deserved being replaced by a girl so much younger than herself. She believed with all her heart that she deserved it, because Derek was fundamentally a good person, and she had hurt him. But now? Four years after the divorce? Addison had to wonder if she still deserved it. Did she deserve the way Derek was treating her, after she had given him everything he wanted after the affair? Addison knew she didn't. She had repented, moved forward, given Derek the space and the life he wanted post-Addison. But it was perfectly clear Derek had not forgiven her. And he was not done punishing her. But there were moments in DC when Derek looked at her like he still loved her, like he still cared. Like maybe Derek could someday forgive her and be the friend he used to be. And then things would shift quickly to the vindictive Derek people often saw in DC, and Addison would be just as confused. There were snippets of the old Derek in there. And while she didn't allow herself to hope, she at least wished they could work together in peace. It didn't seem like too much to ask.

...

When Derek arrived back in Seattle, he had a lot of time to think about what Andrew had said. It's true—he and Addison had wonderful, beautiful, irreplaceable memories together. No matter how much he tried to deny it, to bury Addison in the past, so much of him was because of her, so much of him had been shared with her, and she was a part of him and would be forever. But it's easier to hate her and hurt her than to admit that despite what Addison had done, she was still an important part of his life. It was easier to remind her of her mistakes than own up to his own. And it was easier to be happy with his life knowing Addison wasn't happy with hers. Which of course was cruel. And unfair. And immensely childish. He loved Addison to some degree, knew she was a good person, and she deserved to find someone who would love her and make happy. But something about the thought of someone else doing that made his stomach churn and his throat tight. It was a feeling he would rather not dwell on though. Treading that road was dangerous.

"How was your flight?" Meredith greeted, giving him a kiss on the cheek and taking his coat as he entered the house.

"Long," he replied.

"Are you hungry? There's spaghetti in the fridge," she said as she tucked his coat in the closet.

"I'm not very hungry. Actually I'd just rather go to bed," he said apologetically.

She smiled sympathetically at him and took his hand, leading him to the bedroom.

"Go, rest," she said. "I'm on call tonight though so I'm leaving in a few minutes."

He kissed her modestly on the lips before taking a long hot shower and then slipping into bed, trying his best not to think about a certain red head who bloomed in his head just as the flowers bloomed around him. Sorting through all that mess would have to wait.

---

A/N: That's the first chapter. Thanks for reading!