A/N: Thank you so much for all of the positive feedback on the last chapter! I loved your reviews, and I'm really glad that you're looking forward to more of this story (I am too!). Anyway, here's the next chapter. Thanks so much for reading, and Happy Holidays! :)

"Twins," Derek breathed, meeting Addison's eyes, and smiling widely. "I…I can't believe it," he stammered. "This is so…wow."

"They look healthy too," Jane noted with a reassuring smile. "Everything looks perfect. Why don't I give you two a couple minutes alone?"

"Thanks," Derek nodded, as he and Addison watched Jane's retreating form. "So," he began, once Jane had left the room. "This was unexpected."

Nothing could be further from the truth. Derek was thrilled at the thought of having another baby with Addison. But twins – this was beyond his wildest dreams. But he also knew that even though he was deliriously happy, Addison had her reservations. Three kids were never part of her plan. She had made that abundantly clear over the years.

"Mommy, Mommy, Mommy," a frustrated little voice called out; and Derek and Addison turned to see their five-year-old niece, Heather, tugging at Derek's sister Kathleen's pant leg, trying to get her mother's attention.

"What's wrong, Heather?" Kathleen asked her daughter, crouching down to her level.

"Matthew and Jenny won't let me play with them," Heather pouted. "They never let me play with them."

Kathleen sighed, and turned her attention to Addison and Derek. "Sorry about this," she apologized. "I should probably go deal with this before my kids start World War III. Come on, Heather," she said, standing up and taking her daughter by the hand.

Addison and Derek watched Kathleen and Heather leave the room before turning to each other. "See," Addison began, "this is exactly why I would never want to have more than two kids. Somebody always gets left out. Someone always gets ganged up on. And I don't want that for our kids."

Derek met his fiancée's eyes and smiled. Sure, they had discussed having kids before, but this was the first time they'd ever had such a concrete conversation about it.

"I don't know," Derek chuckled, giving Addison a teasing smile. "I grew up with four other siblings. It wasn't bad."

"Yeah, but kids are meaner nowadays," Addison pointed out. "Just look at Kathleen's kids. I mean, I love them, but poor Heather is always getting left out."

"Our kids wouldn't be mean," Derek smiled, nudging his fiancée playfully. "But, lucky for you, I think two kids is the perfect number, so I'm all for having two kids."

Addison locked eyes with Derek. "Really?" she asked, a smile spreading across her face.

"Yeah," Derek said softly. "I think two kids sound perfect."

"Twins don't run in your family, do they?" Addison asked, ripping Derek from his thoughts and bringing him back to reality.

Derek shook his head. "No. Not that I know of, at least."

"Yeah," Addison muttered thoughtfully. "I don't think that they run in my family either."

"I mean, you are over forty," Derek said lightly. "You know that that drastically increases the chance of multiples."

"I do know that," Addison nodded, meeting Derek's eyes. "But how did you-"

"Addie, I did go to med. school," Derek cut in with a chuckle. "Not to mention, I've spent the last third of my life married to a world-class neonatal surgeon. I'm bound to learn some things about your specialty along the way."

"I guess," Addison conceded with a sigh. "It's just-"

"I know," Derek nodded, rubbing Addison's arm reassuringly. "Three kids wasn't part of the plan."

"And it's not that I'm not happy," Addison admitted. "Because I am. I really am happy. It's just, with three kids, I worry that one of them is always going to be left out."

"It won't happen," Derek insisted. "Have you met our daughter? She's without a doubt the most amazing kid I've ever met. There's no way that Willa would ever leave one of her siblings out."

"What if she's the one who gets ganged up on or left out?" Addison asked in concern. "You realize that twins have a special bond, right?"

"Again, have you met our daughter?" Derek chuckled. "I can't imagine the twins ever wanting to leave their big sister out. And, if for some reason they do, Willa's your carbon copy…do you really think she'd stand for something like that?"

Addison couldn't help smiling at Derek's description of their daughter. "I guess you're right," she admitted, as she allowed her husband's words to sink in.

"I am right," Derek insisted. "And I, I know that three kids wasn't part of the plan…but if you think about it, neither was Willa. And you and I both know that she's the best thing that ever happened to us."

"She is," Addison agreed. "She's better than anything we could have ever planned for."

"Yeah," Derek smiled. "And she's going to be such a good big sister."

Addison nodded. Derek was right. Willa was going to be an amazing big sister and, suddenly, Addison's worries that one of her children would be left out or get ganged up on seemed silly. Willa wouldn't let that happen. And there was no way in hell that she and Derek would let that happen.

"Honey," Derek prodded, when he noticed a slight smile grace his wife's features. "Is everything okay?"

"Yeah," Addison nodded. "Everything's okay." She leaned in and kissed her husband softly. "Actually, you know what," she said, when they broke apart. "Everything isn't okay. Everything's good." She met Derek's eyes and smiled widely. "Everything's really good."

xxxxx

"Hey, do you have a second?" Mark asked, as he lightly knocked on Derek's office door.

Derek looked up from his paperwork and smiled. "Sure, come on in."

"Thanks," Mark grinned, as he sat down across from Derek. "Hey, did you get a haircut? Your hair looks great."

"Mark," Derek chided. "Spare me the compliments. Whatever it is, just tell me."

"Fair enough," Mark chuckled, before quickly growing serious. "Will you be my best man?"

A wide smile spread across Derek's face. "Of course I will. I mean, you were my best man twice, and…of course I will."

"You know, I never thought I'd be asking you that question," Mark admitted.

"To be honest, I didn't think you ever would either," Derek laughed. "But you and Lexie are great together."

"We are, aren't we?" Mark agreed.

"Yeah," Derek nodded. "Hey, uh, while I have you in here…" Derek trailed off, reaching into the pocket of his lab coat and removing a grainy ultrasound picture of his twins. "I want to show you this," he said, handing the picture to Mark, unable to keep the smile off his face.

Mark looked down at the ultrasound picture that Derek had handed him and smiled. "Yours?" he asked, knowing how desperately Derek and Addison wanted another baby.

"Well, Addison's," Derek chuckled. "But, yeah."

"Oh my God," Mark grinned, crossing the desk, and hugging Derek tightly. "Congratulations. That's such good news."

"Yeah," Derek agreed, smiling widely. "It's still early, so we're not telling very many people yet. You can tell Lexie, of course. And Addie's telling Alex and Izzie. But, after what happened the last time, we want to keep things quiet for a while."

"That's understandable," Mark nodded solemnly. "But, Derek," he said, brightening, "this is such good news. You're having another baby."

"Wow, you really were bad at your O.B. rotation, weren't you?" Derek chuckled.

"Hey, I don't remember you being particularly standout either," Mark defended. "If it wasn't for Addison-"

"Look at the ultrasound," Derek instructed.

"Derek, it's pretty grainy," Mark said, as he studied the ultrasound picture in his hand.

"Just look closely," Derek insisted.

"Derek I…wait a minute," Mark said, cutting himself off. "Is that…two babies?"

Derek nodded, unable to keep the smile off his face.

"Twins?" Mark asked in disbelief. "You and Addie are having twins?"

"Yeah," Derek smiled. "We are."

"That's insane," Mark grinned.

"I know," Derek agreed. "I thought that only celebrities had twins…not ordinary people like me and Addison."

"Well, I'd hardly call you two ordinary," Mark chuckled. "You two are pretty much celebrities in the medical world…as am I, of course. But, wait," he said, suddenly growing serious. "Doesn't Addison have that weird thing against having more than two kids?" He had phrased it as a question, but Mark had been to enough Shepherd family gatherings, over the years, to know Addison's stance on the matter.

"She came around pretty quickly," Derek chuckled. "We're both very happy."

"Well, you should be," Mark smiled. "This is such good news. Hey, are you doing anything tonight? Lexie's working late. We should grab a drink at Joe's to celebrate."

Derek nodded. "That sounds good. Addie's taking Willa shopping today, after work, for a dress to wear to your engagement party. So, yeah, I'm free, and a drink sounds good."

"Perfect," Mark grinned. "We have a lot to celebrate."

xxxxx

"Your daughter is precious," rang out a voice behind Addison. She and Willa were in a children's clothing boutique, and Willa and Addison had come out of the fitting room and onto the main floor to get a better look at the dress that Willa was trying on.

Addison turned to the saleswoman, who had walked up next to her. "Thank you," she smiled.

She looked back at her daughter. The saleswoman wasn't wrong. Willa looked truly adorable in the navy, drop-waist, pleated dress that she was wearing.

"She's such a little grown-up too," the saleswoman complimented, as she and Addison continued to watch Willa, who was admiring the dress she was trying on in the store's full-length mirror.

"She is," Addison agreed with a smile. "I always say that she's three going on thirty."

"Well, she really is adorable," the saleswoman nodded. "I'm pretty sure that the dress she's wearing right now was made for her, but if you need anything else, just let me know, okay?"

"Okay," Addison smiled, turning her attention back to her daughter, as the saleswoman walked away.

"Pretty dress," Willa murmured, as she studied her reflection in the mirror.

"Pretty girl," Addison smiled, running her hand through her daughter's dark brown hair. "I think this is the dress, Willa. What do you think?"

"Yeah," Willa nodded.

"Okay, let's get you changed out of this dress, and Mommy will buy it for you. Does that sound good?"

"Yeah," Willa smiled, as she and Addison walked back to the fitting room. "Thank you, Mommy."

Addison pressed a kiss to Willa's temple, and smiled. Dress shopping. It was one of the many things she loved about having a daughter. And, in her three short years, Willa had proven to be an excellent shopping partner. Of course Derek had predicted that early on.

"Okay, not that this was ever up for debate," Derek chuckled, as he bounced his eleven-month-old daughter in his arms, "but Willa is definitely your daughter. She was so fussy this morning, and then the second that we got to the mall, she calmed down completely."

Addison smiled, as she ran her hand over a cream dress in Willa's size. "What do you think about this dress for Willa's first birthday?" she asked her husband.

"I like it," Derek nodded. "I mean, we pretty much have the cutest baby ever. She's going to look adorable in anything…but I do like that dress. Hey, wait, what do you think of this dress?" he asked, gesturing towards a tiny silver dress. "You can tell me if you hate it," he said after a moment.

"I don't hate it," Addison smiled. "I like it a lot, actually."

"Really?" Derek asked in surprise.

"Really," Addison nodded.

"As much as the dress you chose?" Derek teased.

"Well, maybe not that much," Addison laughed. "But I do like it."

"You know, this store is pretty cute," Derek admitted, as he looked around the boutique.

"I never pegged you as the type to get all gaga over baby clothes," Addison chuckled. "I mean, most men don't."

Derek shrugged. "I don't know. With the right woman and the right baby…" he trailed off, meeting Addison's eyes. "Hey, it looks like Willa is totally in her element, here," Derek chuckled, motioning towards their daughter, whose eyes were wide in delight as she looked around the boutique incredulously. He pressed a gentle kiss to his daughter's temple and smiled. "You're going to be Mommy's little shopping partner, aren't you?"

Derek had been completely right. Addison loved taking Willa shopping. And as she stood in the fitting room with her daughter, Addison couldn't help getting a little teary eyed as she imagined going dress shopping with her daughter for other important dresses down the road. A flower girl dress for Mark and Lexie's wedding in the near future. A dress for Willa's first school dance in the not so near future. A prom dress in the very distant future. And, one day, a wedding dress.

"Mommy," Willa said softly, ripping Addison from her thoughts. "Mommy sad?"

"I'm okay," Addison reassured her daughter, as she reached into her purse, retrieved a tissue, and carefully dabbed at her moist eyes. Hormones were clearly to blame for this she decided.

"Really?" Willa asked, unconvinced.

"Yeah," Addison nodded, touched by her daughter's compassion. "Hey, what should we do next?" she asked, trying to lighten the mood. "We could get frozen yogurt…or we could get hot chocolate from Starbucks."

Willa looked thoughtful, as she weighed her options carefully. "New shoes for Mommy," she suggested.

Addison smiled. "You think Mommy needs new shoes?" she asked, as she helped Willa out of her dress, and back into the clothes that she had been wearing earlier in the day.

"Yeah," Willa nodded, taking her mother's hand, as they walked up to the cash register to pay for Willa's new dress.

"That sounds like a pretty good idea," Addison admitted. "What kind of shoes should Mommy buy?"

"Heels," Willa answered automatically; and Addison couldn't resist smiling at that. She knew her heel-wearing days were numbered; so why not buy one more pair while she could still wear them?

"Okay," she agreed, bending down to pick Willa up. Sure, Willa could technically walk on her own, but there was a part of Addison that wanted to carry her daughter around while she still could. Like her heel-wearing days, her days of being able to carry Willa around were also dwindling. She turned to her daughter and smiled. "You ready?"

Willa nodded, and clutched her mother tightly.

"Okay," Addison smiled. "Let's buy some heels."

xxxxx

"I feel like my tan is completely gone," Izzie complained, as looked down at her bare arms. "This dress would look so much better with my honeymoon tan."

Addison couldn't help laughing at her friend's complaint; Izzie looked picture-perfect in the red, sleeveless dress she was wearing to Mark and Lexie's engagement party. "First of all," Addison chuckled, "I'm pretty sure you don't need me to tell you how incredible you look. But I will…you look incredible. And your honeymoon was over a month ago," she added lightly. "And it's not like you've had much time to work on it lately….you know, between work and living in Seattle."

"I know," Izzie sighed. "It's just, I miss my post-honeymoon glow."

"I don't know," Addison chuckled. "I'm pretty sure your post-honeymoon glow had nothing to do with your tan."

"Funny," Izzie smirked. "But not entirely wrong. But speaking about glowing…" Izzie trailed off, gesturing towards Addison. "You definitely-"

"Oh, shut up," Addison interrupted with a chuckle. "I spent the better part of today hugging a toilet. The only glowing that's happening around here is a result of me being paler than usual."

"So the morning sickness is hitting you hard?" Izzie asked sympathetically.

"Yeah," Addison nodded. "And it tends to be worse with twins, so it looks like I'm in for a rough couple of months."

Izzie nodded empathetically. "So when are you and Derek planning on telling Willa?"

Addison bit her lip. "We're going to wait until I'm out of the first trimester. You know, just in case…" she trailed off, doing her best not to think about her previous miscarriage.

"So, this is a great party," Izzie grinned, quickly changing the topic of conversation, when she sensed Addison's discomfort.

"Thanks," Addison smiled, as she looked around the room. She and Derek had offered to throw Mark and Lexie an engagement party at their house and, from the looks of it, everyone seemed to be having a good time.

"Hey," Derek smiled, as he and Alex walked over to join Addison and Izzie.

"Hey," Addison smiled. "I was wondering where you guys were."

"Willa was tired," Derek explained, "so Alex and I put her to bed."

"Oh," Addison nodded. "Did she want me to come up and say goodnight to her?" Whenever their work schedules allowed, Derek and Addison tried to put Willa to bed together at night. And, truth be told, it was something that Addison had come to enjoy as much as her daughter did.

"I told her you'd be up in a little while to give her a kiss goodnight," Derek reassured his wife. "I think she was pretty excited though…it's not every night she gets a bedtime story from Uncle Alex."

Addison gave Alex a warm smile. "What'd you read to her?"

"Read to her?" Alex scoffed. "This clown," he said, gesturing towards Derek, "told me that Willa likes it when you make up your own bedtime stories."

"You made up a bedtime story?" Izzie laughed, placing a hand on her husband's bicep.

"Not a good one," Alex chuckled.

"Oh, please, Willa loved it," Derek insisted. "And I loved seeing you squirm."

"Remind me, why am I friends with you?" Alex teased.

"Well, technically, you seem to be better friends with my wife," Derek laughed. "I'm just an added bonus. And I guess it doesn't hurt that I throw great engagement parties."

"Speaking of which," Izzie cut in. "Has anyone seen Mark or Lexie lately? I mean, this is their engagement party. I feel like I haven't seen them all night."

"If I know Mark," Derek chuckled, "he and Lexie are probably going at it in one of our bathrooms or guest bedrooms or something."

"That's an image I could have lived without," Izzie chuckled.

"What is?" Mark asked, as he and Lexie joined the group, flutes of champagne in both of their hands.

"Oh, uh, nothing, nothing," Izzie stammered. "Where have you two been anyway?"

"You know what," Derek cut in before Mark could answer. "It's actually probably better if you don't tell us."

"Okay," Mark shrugged innocently.

"Hey, thanks again for throwing us this party," Lexie said, shooting Addison and Derek an appreciative smile.

"Oh, please, we're happy to do this," Addison insisted.

"We really are," Derek agreed. "And, hey, we haven't toasted your engagement tonight," he smiled, raising his champagne flute.

"Well, you know I'd never say no to a toast in my honor," Mark winked.

Derek shot his best friend an amused smile, before raising his champagne flute. "Congrats you two," he toasted; and everyone tapped their glasses against his.

"And while we're toasting good news," Mark smiled, looking at Addison and Derek. "I know tonight's supposed to be about me and Lexie, but we're happy to share, so cong-"

"Let's not toast us just yet," Addison cut in uncomfortably. "I…I…we're excited….really. We're just…we should probably hold off on celebrating anything just yet. Besides," she added with forced cheerfulness, "let's keep tonight about you two."

Mark nodded sympathetically. He knew that Addison and Derek were ecstatic about the twins. But he also knew that they were cautiously excited. He knew that another miscarriage was a very real fear for them, and that they didn't want to get their hopes up only to have them slashed again.

"Okay," he grinned, determined to take the unwanted attention off Derek and Addison. "In that case, we really should toast me and Lexie again."

xxxxx

Addison had just finished giving her sleeping daughter a kiss goodnight when she felt Derek's arms around her waist.

"Hey," she whispered in surprise. "Why aren't you downstairs at the engagement party with everyone else?"

"I could ask you this same question."

"I was kissing our daughter goodnight," Addison defended. "And I might have needed to get away from everything for a minute," she admitted reluctantly.

Derek smiled. "Come with me," he said, taking Addison by the hand, and leading her into their bedroom.

"Honey, we really should get back down-"

"It will only take a second," Derek insisted, leading her to their bed. He went over to the nightstand, and retrieved two glasses of water. "Here," he said, handing her a glass.

Addison accepted the glass of water, and looked at her husband skeptically.

"Toast our good news with me," Derek said softly.

"Der."

"I know you're worried," Derek started. "I am too. But, Addie, right now, everything's fine. We're having twins, and that calls for a celebration…or at the very least a water toast."

Addison smiled as she let her husband's words sink in. He was right. "Okay," she agreed. "But under one condition."

"Name it," Derek nodded.

"When I make it past the first trimester, we go out and celebrate…you know, nice dinner, dancing, dessert, sex…the works."

A wide smile spread across Derek's face. "I can't wait for that," he grinned. "But, until then…" he trailed off, holding up his glass of water. He met Addison's eyes and smiled. "To our twins," he said softly, raising his glass.

Addison lightly tapped her own glass against her husband's glass, and smiled. "To our family."