A/N: This story takes place about six years after the finale of season three and is about an eventful time in the lives of some of our favorite doctors. It focuses primarily on MerDer, Addex, and McStizzie, though the other characters do occasionally appear. The first chapter acts mostly as a background to how things have developed over the past few years, though the ending of the chapter does get the plot rolling. The story will hopefully be filled with drama, angst, sex, romance, humor . . . basically anything I can fit in here. I hope you like it!

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A giant smile was plastered on Derek's face as he gazed through the plate-glass window of the nursery of the Seattle Grace Maternity Ward. His eyes jumped from one infant to another, studying their expressions with awe. He could feel his grin widen as he focused on a tiny bundle in the row closest to the window, the dark-haired little boy swaddled tightly in a thin blanket as his wide eyes darted across the ceiling.

Derek nearly jumped out of his skin when he felt a hand slap lightly against his shoulder, the goofy grin faltering. He knew instantly who the hand belonged to without even turning around, and he rotated his head sideways to glare playfully at his best friend.

Mark smirked, his eyes darting between the window of the nursery and Derek's teasing glower. "Daydreaming, buddy?"

"Shut up, Mark," Derek answered, but the smile on his face coupled with the bantering tone of his voice betrayed his attempt to appear irritated.

Though the process had been gradual, Mark and Derek had made an effort to repair their relationship, and now, years after the actual catastrophe that had driven them apart in the first place, they could honestly claim to be as close as they were growing up. After so many months of hostility, the two had eventually decided to put their ugly history behind him, especially when it became apparent that all parties involved had moved passed the adulterated event.

Derek, of course, had moved on with Meredith. Their relationship had been rocky at first, but as Meredith adjusted to the ways of being a relationship person and Derek had realized how to balance the priorities in his life, the two had quickly learned how to make things work. The fresh start, which began weeks after Burke had left Cristina on her wedding day, had been exactly what the couple needed. Their reconciliation had been slow, both fearful of having their heart ripped apart yet again, but it soon became obvious that they both wanted the same things; that they both wanted to move beyond the hurt they'd caused one another and start over.

Just as Derek had found himself moving on with Meredith, Mark, too, found a new woman to turn his life around. The once untamable bachelor had met his match with Isobel Stevens, a woman who not only fearlessly put him in his place when he opted to use his sarcasm and brash comments in her presence, but one who had also effortlessly worked her way into his heart. The attraction between the two was of no surprise to either of them; in fact, they were both willing to admit that some sort of affair between them was probably inevitable. What did catch them off guard, however, was the way in which their physical attraction combined with their equally feisty spirits, causing a nearly explosive reaction when they'd first taken one another in the shower of the resident's locker room. The unexpected meeting, an effect of an especially stressful day in the OR and a growing loneliness in the pit their hearts, could have easily been a one time thing, but as they'd panted against one another as steam rose around their bodies, they both knew without a shadow of a doubt that it wouldn't be.

It was in great part due to their growing relationships with these women that Mark and Derek finally started to make amends for everything that had transpired between them. The transition from enemies to friends occurred over breakfast in the wee hours of the morning, the two of them inevitably running into one another as they stumbled from Izzie and Meredith's neighboring bedrooms. The looks of animosity over their cups of coffee had eventually turned in to looks of tolerance, the tolerance inevitably leading to a shared acceptance, and in the span of only a few months, the two men were sharing sections of the Seattle Times and occasionally meeting in the foyer for an early morning run.

The recuperating friendship between Mark and Derek was thrilling for Izzie and Meredith, who actually grew closer to one another as their significant other's repaired their relationship. On the rare occasion that the four of them found themselves not on the schedule at Seattle Grace, they often made plans together, grabbing drinks at Joe's or catching a movie at the downtown theater.

On a normal Sunday morning, eight months after Mark had begun seeing Izzie and nearly twelve since Meredith and Derek had righted what was wrong with their initial relationship, Mark and Derek had found themselves entering the kitchen, sweat dripping down their backs as they struggled to catch their breath from a three mile run around Queen Anne Hill. Mark went straight to the refrigerator, grabbing two bottles of water and tossing one to Derek as they sat down at the table for a light breakfast before showering and heading to the hospital.

It was just as Mark was handing Derek the sport's section of the newspaper that they were reminded of why they had been so distant for their first few months in Seattle. Mark's eyes widened as he caught sight of the figure in the doorway, his dropping jaw causing Derek to turn around to inspect what was so astounding. It was at this moment that Derek saw his ex-wife traipsing in the room, walking confidently as though her presence in the Meredith's kitchen was no odder than the fact that the sun rose each and every morning. Mark and Derek exchanged flabbergasted glances as she helped herself to a cup of coffee before casually walking over to the table and plopping down between them.

"Good morning," she yawned, taking a sip of the lukewarm liquid that filled the coffee cup which Meredith drank from morning after morning.

Mark narrowed his eyes, looking at her incredulously. "Uh, good morning, Addison."

Addison took another sip of her coffee, ignoring the shocked stares of the two men as she stole the society pages from Mark's hands. The room was quiet as her eyes scanned the spreads, Mark and Derek unsure what to say as the elephant in the room continued to grow with each passing second.

Finally unable to stand his curiosity anymore, Derek leaned against the table, his gaze intent as he stared at Addison inquisitively. "Um, what the hell are you doing here?"

Addison looked up from the paper, her head cocking to the side as she grinned at Derek. "What am I doing? Um, I'm doing Alex Karev."

The statement was said with such matter-of-factness, Mark and Derek couldn't help but crack smiles. "Karev?" Mark repeated with a disbelieving grin. "You're sleeping with Alex Karev?"

Her eyebrow lifted as she looked at him with a confident expression. "Isn't that what I just said?"

Mark pursed his lips, nodding his head slightly as he glanced at Derek bemusedly. Addison caught the exchange, rolling her eyes. "Do you think we could skip the whole awkward exchange? I'm really not in the mood."

Derek stifled a smile, strangely comforted by Addison's assertive attitude. "Well alright then," Derek mumbled, and with simultaneous nods, he and Mark picked up their section of the papers. And with that, Addison was officially inducted into their breakfast club.

Derek and Mark followed through with their promise to forgo the awkwardness that could have arisen with the current living situation. The circumstances turned out to be unexpectedly pleasant and comfortable between everyone sleeping under the roof, everyone getting along surprisingly well when they all happened to be sleeping over at the same time. In place of the awkwardness, though, was the unavoidable feeling of claustrophobia, which could be felt to the fullest extent in the mornings when the six of them were scurrying to get ready for rounds.

The congestion reached its peak one morning as Izzie yelled at the top of the stairs, her frustration spiking as Alex and Addison's shower marathon stretched into the thirty minute mark. Mark sighed in the kitchen as he glanced at Meredith and Derek across the breakfast table, all of them hearing Izzie's irritated screeches as she demanded her turn in the bathroom.

"This house is way too crowded," Mark acknowledged, tearing off a corner of his bagel and stuffing it in his mouth.

Derek nodded, only half paying attention as he scanned an article in the World Medical Journal. "Yeah, you should definitely leave," he mumbled, his tone teasing as his lips curled upward.

Mark flashed a smile. "Maybe I will. Maybe I'll ask Izzie to marry me, and we'll move far away from you insatiable perverts."

No one was exactly sure how Mark's teasing comment had led him to the high-end jewelry store that very afternoon. The strange thing was, though, there wasn't a doubt in his mind as he'd handed his credit card to the saleswoman, the small velvet box containing a platinum engagement ring already weighing heavily in the depths of his pocket. His confidence in his decision had only been substantiated when he'd seen the tears in Izzie's eyes two weeks later as he'd knelt down on one knee, her smile growing as she'd uttered the word yes over and over, her lips suddenly covering nearly every inch of his face until they'd finally settled on his mouth.

Izzie's excitement over her upcoming nuptials was seemingly contagious, Meredith and Addison suddenly thrilled by the news as they helped her prepare for what was quickly shaping into her fairytale wedding. Addison easily wormed her way into the tight friendship that Izzie and Meredith had formed over the past year, growing especially close with Izzie as she readily volunteered to gang up on Mark with her. Together, the three of them planned and conspired, and within four months, Isobel Stevens transformed into Mrs. Mark Sloan.

Mark and Izzie's happily-ever-after only seemed to strengthen the relationships of the other two couples. Seeing their friends as blissful newlyweds was like an affirmation that such things really did happen. It was this very affirmation that allowed Meredith to accept Derek's proposal when he finally mustered up the nerve to ask her to marry him six months later. The engagement was a long one, both of them enjoying the newest stage of their relationship, but when they finally exchanged vows in a tiny chapel on the bank of Elliot Bay more than a year and a half later, the words they uttered were meant with such complete sincerity, neither one felt a single qualm as they'd slipped the simple bands onto each other's ring fingers.

That cold November day was soley about Meredith and Derek, and it was for this reason that Izzie was actually able to keep a secret for the first time in her life. As she watched her friends exchange vows from her place at Meredith's side, her eyes would periodically roam to Mark's across the aisle, both of them exchanging knowing grins as their thoughts flowed concurrently. Mark's eyes sparkled as his gaze roamed to his wife's flat torso, his chest virtually ablaze with happiness as he pictured the child that was growing within, a child that they had only found out about seven hours before.

William Bennett Sloan was born on June 28th of the following year, his initial screams of life bringing tears of joy to the eyes of everyone in the room. Mark and Izzie hadn't been able to take their eyes off of their tiny son for the first hours of his life, their smiles never faltering as every move he made took their breath away. Parenthood had been an amazingly easy transition for them, both of them happily doting on their child as they'd watched him develop. Ben's vibrant brown eyes captivated everyone around him, and the grin that he flashed, which Izzie insisted was an exact replica of his father's, had the power to melt the hearts of everyone who knew him.

In addition to the obvious joys that parenthood brought her, Ben's arrival also allowed Izzie to rekindle her long-strained relationship with George. Though their friendship had never been the same after their brief, yet disastrous affair just after George's father had passed away, they were now able to find common ground with the arrival of their children. Callie and George had welcomed Samuel Harold O'Malley to the world only four months before Ben had been born, and their similar familial situations impelled them to come to a silent understanding, which eventually led to a comfortable companionship between the two families.

Mark and Izzie's new focus on being parents did little to quiet the relationships they'd developed with Meredith and Derek and Addison and Alex. The three couples continued to enjoy their friendships as they had for the past few years, the friendships that had begun with a simple unofficial breakfast club. Now, though, there was a new member, a tiny person who had somehow managed to acquire all the best features of Izzie and Mark and compile them in a way that left everyone fussing over his every need.

It was on Ben's second Christmas that Alex stole Addison's breath in the most unexpected way. She was sitting on his lap, her head resting against his as they watched Mark reading Ben The Night Before Christmas. The little boy was smiling as his father read the words, his eyes wide with excitement as he remained totally entranced by the images imprinted on the page. Alex smiled at the sound of Ben's quiet giggle, his face turning so that his lips were pressed against Addison's ear. "I want that, what they have; I want a family. I want you to be my family."

Addison turned to meet Alex's gaze, her face guarded as she studied his expression. "Alex…" she whispered.

His hand had slipped over hers, and before she knew what was happening, he'd slipped an engagement ring on her finger. "Marry me, Addison."

Though they had been together for nearly four years, they had only talked sporadically about the possibility of marriage. The news about her infertility that Addison had received during her brief trip to Los Angeles all of those years before had effectively crushed her dream of having a family, so she had never felt the need to push her relationship with Alex in any particular direction. They were both wonderfully happy with the way things were, both in agreement that things couldn't possibly be better between them, even if they had a tiny piece of paper legally binding them together for life. But as she stared at her diamond-clad finger in the midst of the room filled with the people who'd grown to be their family, Addison couldn't imagine anything that she wanted more than to have Alex Karev as her husband. With a smile on her face, she'd pulled his face to hers, the soft brush of her lips an obvious acceptance to his question.

The holidays left everyone reeling with happiness, and the future was looking up as the New Year stuck. Everyone seemed to be content with the way things were going, excited by the direction of their careers and their personal lives. This is why it was such a traumatic morning for Meredith when, in the second week of February, a tiny stick turned blue right before her eyes. She swallowed, blinking her lashes over and over in the hope that she could somehow clear away some sort of temporary color-blinding phenomenon, but the pregnancy test remained the same shade of nauseating blue no matter how hard she tried to convince herself that she wasn't pregnant.

Addison confirmed the news after a quick examination, pilfering Meredith's hope that the home pregnancy test had been wrong. A baby was not what she was expecting this year to bring, and though she knew Derek would be over the roof with excitement, she couldn't contain her own suffocating nerves at the prospect of becoming a mother.

She was, of course, correct in her assumption that Derek would relish the idea of having a baby. She couldn't recall a time since they'd met that she'd seen such a joyous look on his face as the one she'd seen when she told him about the pregnancy. From the moment he'd received the news, he'd committed himself to pampering her, wanting to take care of her every need as she grew their child in her womb. Though the pregnancy had caught them both off guard, his excitement over his impending fatherhood continued to steadily increase with each month, often leaving him feeling as though he were going to burst with happiness whenever he thought of his child. He was completely enthralled with Meredith's ever-growing belly, and as her pregnancy wore on, it was not uncommon for his wife to express her annoyance over his incessant doting. Derek knew, though, that she was far from annoyed. If anything, she was relieved that he was excited enough for the both of them. Although there was no doubt in his mind that Meredith would love their child, her worries over inheriting the bad mommy gene only grew worse as she approached her due date.

Luckily, Izzie was able to supply some relief for Meredith's fears about her encroaching motherhood. Izzie's excitement over Meredith's pregnancy almost matched Derek's. She was constantly encouraging Meredith and reassuring her that she was nothing like Ellis Grey, promising her that she was going to make a great mother. Though Derek often provided his wife the same assurances, it seemed that Meredith typically took greater comfort in Izzie's female opinion, almost certainly because Izzie had been through pregnancy herself.

Now, as Meredith entered her seventh month of pregnancy, Derek could barely contain his excitement. It was this very excitement that often led him to the maternity ward of the hospital, his enthusiasm over his impending fatherhood leading him to peer at the newly arrived infants through the glass pane. Mark's laughing expression when he caught him at the glass had Derek rolling his eyes, walking away from his friend as he continued down the hallway. "What do you want, Mark?"

Mark laughed, shrugging his shoulders as he rushed to catch up to Derek. "Oh nothing; we just have a quiet board today, and I've already run out of things to do."

"Don't you know you're not supposed to talk about a quiet board?"

Mark rolled his eyes. "Oh please; I don't buy into that superstition bullshit."

Derek was about to reply when he noticed a spirited blonde heading straight for them, her speed quick as she balanced a tiny boy on her hip. "Hey, there're Ben and Izzie."

Mark looked up, grinning with surprise when he saw his wife and son. "Hey, what're you two doing here?"

"Daddy!" Ben squealed, hurling himself into his father's arms the moment Izzie was standing before him. Mark laughed, pulling Ben against his chest as he offered Izzie a light kiss.

"We just came by to pick up Meredith since her shift's over. I convinced her that we need to go shopping for the nursery if…you know…she wants to have somewhere to put the baby when he's born."

Derek smirked. "Good thinking. Where is she?"

"I'm here," Meredith announced, walking up to the group as the question crossed her husband's lips. "Your son has decided to use my bladder as a freaking lounge chair, so I had to run to the restroom. Again. For like, the trillionth time today." Derek grinned, his hands rising to her shoulders and massaging gently.

Derek continued to knead the knots in her shoulders as the five of them chatted in the middle of the hallway. Ben's face contorted in excitement when his father asked him what he'd done that day. "I got my hur wet, Daddy," he animatedly replied, touching his blonde locks as though it were proof.

"You got your hair wet?" Mark asked, looking at Izzie.

She laughed at her son, kissing his forehead lovingly. "I took him to the pool at Addison and Alex's apartment," she told him with a grin, turning to look at her son. "Baby, tell daddy what a great swimmer you are!"

Ben giggled, smirking at his mother. "I can kick, kick, kick!" he squealed, flailing his legs in the air to demonstrate.

Addison and Alex were laughing as they walked hand-in-hand toward the group, humored by the image of Mark holding Ben away from his body as he tried to avoid being inadvertently kicked by the enthusiastic boy. Addison smiled when Ben's eyes lit up at the sight of her, and she held her arms out in Ben's direction, laughing when the toddler giggled as he threw himself in her direction. "Hey, sweetie," she said with a smile, kissing the top of his head lightly.

"Hi!" Ben greeted in a high pitched voice, his arms swinging around Addison's neck as he grinned at Alex over her shoulder. "Awex!"

Alex laughed. "Hey little man," he said, giving the boy a soft high-five. "Are you excited about your birthday party on Saturday?"

Ben nodded energetically at the thought of the birthday party his mother had been planning for weeks, his face flushed with excitement as he held up three fingers for everyone to see. "I'm going to be free years old!"

Izzie smiled, her hand rising to rub Ben's back. "My baby's getting so old."

Ben scowled at her, shaking his head. "I'm not a baby, Mommy. I'm big!"

"Oh course you are," Izzie indulged, grinning widely as she took him from Addison. Looking at Meredith, she raised her eyebrows. "We should probably go if we want to actually get to the stores before they close."

"Okay." Meredith leaned against Derek, kissing him. "I'll see you at home."

"You guys have fun," Mark told them, touching his nose to the tip of his son's. "Love you," he told him. Turning to Izzie, he captured her lips in his in a brief kiss. "And I love you, too."

"Love you, Daddy!" Ben said happily, his arms wrapping around Izzie's neck as she grinned at her husband. Mark watched them walk away, smiling at the sight of his wife and son dissolving into giggles as Izzie tickled Ben's neck with kisses on their way to the elevator.

Meredith and Izzie walked to the parking lot, easily finding Izzie's Ford Explorer. As Izzie strapped Ben into his car seat, Meredith plucked the car keys from her hands. "I'll drive," she said. "You drive like a grandma. We definitely won't make it to the stores before they close if you don't let me behind the wheel."

Izzie rolled her eyes. "I do not drive like a grandma," she told her, acting offended as she tickled Ben before shutting his door. "I'm just cautious."

"Yeah, cautious being code word for grandma," Meredith said with a laugh, walking around to the driver's side.

Izzie opened the passenger door, sitting in the seat in front of Ben. "You're going to love this boutique, Mer," she told her as Meredith pulled out of the parking lot. "I'm telling you, you're going to be a hundred times more excited about the baby after you decorate the nursery."

Meredith rolled her eyes at Izzie's enthusiasm. "It's not that I'm not excited; I'm just scared shitless."

Izzie glared at her, checking on Ben in the backseat to see if the toddler had noticed Meredith's bad language. Luckily he hadn't, his eyes focused out the passenger window as he babbled to himself.

Meredith sped down the road, driving quickly as she followed the directions Izzie was giving her. "It's only a few more blocks up the street," Izzie offered, smiling as she heard Ben begin a rendition of the theme song to Sesame Street as his legs dangled against his car seat.

Meredith groaned when her cell phone rang moments later, her hand reaching out and pulling her purse from the floor of the back seat. She dug through the contents of her purse blindly, the ringing continuing as her hand refused to connect with the shrilling device. "Want me to look for it?" Izzie offered.

"No, I think I can get it," Meredith said, looking into her bag. Holding the steering wheel with her free hand, she spotted the glow of the screen at the bottom of the purse and wrapped her hands around it. "Got it," she said, pulling it out and looking at the caller ID.

She looked up sharply when she heard Izzie frantically scream. "Meredith!" An instant later, she felt the SUV lurch to the left as a car plowed into the passenger side of the vehicle, Izzie's car spinning through the intersection before coming to a halt against a telephone pole on the opposite side of the road.

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