Addison smiles at Derek, when he sees him sitting on the couch in his living room, he smiles back and then gets up helping her with Chris and the suitcase. Pete approaches his girlfriend and kisses her lips while stating:

"I'll miss you at the party."

"Tomorrow I'll be back. Have fun and give Monica a hug for me."

"I love you."

Pete affirms before grabbing her around the waist and giving her a soft kiss.

Derek tries to occupy himself with his son, but the scene causes a pang in his chest and he walks away taking his son out of the house. As soon as he hears the sound of the door, Addison walks away from Pete, she gives him one last peck and states:

"We need to go."

Pete nods and takes her hand leading her to the car, where Derek is propped up playing with his son.

Pete finally lets go of Addison's hand, gives her a kiss on the forehead and asks:

"Drive carefully, Addie."

"Ever."

"And call me as soon as you arrive."

Addison nods, Pete approaches Derek, gives Chris a kiss on the forehead and whispers:

"Happy New Year, buddy."

Then he waves at Derek and walks out to his own car.

As Pete drives away, Derek starts to get his son into the car seat and once the boy is safe, he sits in the passenger seat and smiles slyly at Addison, while stating:

"He just missed peeing on you."

"Derek, don't be childish."

"Peter that was childish."

"Pete is uncomfortable with the situation, okay? If you put yourself in his shoes, imagine your twelve-year-old girl spending New Year's with one of the thousand ex-boyfriends she must have."

Addison teases and Derek lowers his eyes, overcome by her argument. After a moment of silence, he apologizes:

"I'm sorry, it was wrong to talk about Peter like that. Especially since you're being so kind to me."

"Fine. Sorry about the way I talked about Meredith too."

Derek just nods and then starts rummaging through the CDs in her car, soon he finds what he was looking for and states triumphantly:

"You kept The Essential."

"Only because I forgot this thing was there."

"I believe in you. Now let's listen."

"There's no way I'm going to go to Connecticut and listen to The Clash."

"Yes there is. You'll hear it for all the times I've heard your boring pop songs from here to Connecticut to the Hamptons..."

Addison just rolls her eyes and Derek puts on the cd. As soon as the melody starts Chris shakes his little hands and lets out a little scream, which makes his father euphoric:

"He liked! Our son has better taste in music than you, Addie."

Addie sticks her tongue out, but smiles as she watches her son in the rearview mirror.

AAAA

When Addison parks the car in front of Carolyn's house, Derek gets out and lifts her son out of the car seat before escorting her toward the door. As they start up the stairs, the door opens and a smiling Mark Sloan emerges from inside the house, Derek immediately freezes and Addison feels her stomach sink.

As soon as Mark notices their presence, the smile disappears from her face and he approaches asking:

"You together? What about the charlatan you flaunt around the hospital, redhead?"

"What are you doing here?"

Derek asks through gritted teeth and Mark explains matter-of-factly:

"Visiting Mom on holidays like every year."

The provocation does not go unnoticed and Derek approaches, facing his former friend while saying:

"You have a lot of guts to still come here after all."

"Why if she comes?"

Mark asks pointing to Addison who swallows hard and is surprised to hear Derek defending her:

"She is the mother of my child."

"Oh yes yours she kept."

Mark plays with a wry smile looking down at the sleeping baby on Derek's lap, and Addison feels tears welling up in her eyes. Derek immediately turns to him and asks already annoyed:

"What is he talking about?"

"You do not know?"

"Mark, please!"

"Typical for Addison Montgomery to go to Seattle after you keeping that secret. She lived with me after you left, stayed in my apartment for two months, we were a couple. Then she got pregnant, had na abortion without asking my opinion, and went into first plane to Seattle to save the marriage."

Mark speaks every word with disdain. Derek stares at Addison in shock, before he can say anything, Nancy appears and noticing the mood, pats Mark's arm while asking:

"You weren't on your way out, Mark?"

Mark nods and gives Derek one last look stating:

"I felt like you needed to know."

Having said that, he walks away walking towards the car.

Derek clutches his sleeping son in his arms and hurries up the stairs past Nancy. Behind him Addison calls out her name, but he just ignores it and bursts through the door of the house.

Addison enters right behind begging:

"Derek, please listen to me!"

"Listen to what? Don't you think it's too late to tell me anything?!"

"Derek, please!"

"You lived with him, got him pregnant and kept it from me."

"I wanted to tell you, but..."

"Go away!"

"Derek..."

"Get your car and go back to New York!"

"I'm not going without Chris!"

Addison says reaching out to catch Chris, but Derek just holds him tighter and retorts decisively:

"My son stays with me."

"Our son!"

"Our son stays, as he won't spend another date away from his father because of his mother's questionable character!"

"Derek, think about what you're saying!"

Nancy, who until then had watched in silence, decides to intervene. Derek is not intimidated:

"Oh, I'm thinking about it very well, I'm thinking about the three months I lost of my life trying to forgive this one."

"The three months you were punishing me, you mean!"

"And you expected less after revealing the Montgomerys' hereditary infidelity."

The phrase hits Addison like a slap and she feels her eyes water again, angrily she demands:

"Give up Chris!"

"No! Go away now!"

Derek screams already totally out of patience and Chris jumps into his arms, the little boy starts to whimper and despite Derek's efforts he extends his arms calling his mother. Derek begrudgingly hands over his son to Addison, who snuggles him in her arms, saying that everything will be fine.

Derek looks at his frightened son in his ex-wife's arms and at Nancy and Carolyn's disapproving looks, he runs his hands through his hair and runs upstairs.

Addison sits heavily on the sofa with her son still weeping in her lap, she clutches him to her chest, her eyes downcast, embarrassed by the scene.

As soon as the baby seems a little calmer, she turns to Carolyn saying:

"I'm very sorry."

"You didn't do anything wrong, Addie."

Nancy calms down by squeezing her ex-sister-in-law's shoulder, who takes a deep breath and starts to get up:

"I'm leaving, I'm going back to New York."

"I won't let you drive like that."

Carolyn speaks for the first time in a firm but affectionate tone, but Addison insists:

"I'll leave Chris here with you, don't worry."

"It's not just Chris I'm worried about."

Carolyn speaks truthfully and Addison sits back down, rubbing her face as she fights back tears.

Addison rocks her son for long minutes and as soon as she notices him sound asleep she hands him over to her ex-mother-in-law who asks worriedly:

"You're not leaving are you?"

"I'll talk to your son."

Addison speaks in a firm tone and quickly walks away up the stairs.

Derek is lying in his old bed when he hears the knock on the door, he just ignores it, but soon Addison's voice echoes:

"We need to talk, Derek."

"You still haven't left?"

"No and I won't until we talk."

"Then you'll spend the day planted there, because I don't have anything to say."

"Derek, please. You said yourself that you wanted to give Chris a good family time."

"You are not my family, never have been. You are na adulteress cretin."

Derek yells angrily and Addison gulps backing away from the door.

As she is approaching the stairs, she hears her ex-husband's voice calling her name, she turns around and sees him standing in the bedroom doorway.

Addison and Derek stare at each other in silence until he says crossing his arms:

"You have five minutes."

She nods and makes her way back to the bedroom, where he lets her in and closes the door.

Addison sits on the bed while Derek remains by the door, standing with his arms crossed. After a moment of silence, he states arrogantly:

"Your time is running out."

Addison sighs deeply and starts talking nervously while playing with her hands:

"I was devastated when you left and when Nancy showed up to pack your things I couldn't stay in that house without you anymore. And Mark was still there, he was still being good to me... He kept saying he loved me and I I liked him too and I didn't want to believe he had thrown our marriage away for nothing."

Addison stops talking for a moment, taking a deep breath and fighting not to cry. Derek just stares at her with the same arrogant expression and then she continues:

"I kept calling you and wearing your rings and it hurt Mark. At some point I got careless and ended up getting pregnant, at the time I didn't know what to do and told him, but he cheated on me and I didn't want to have one son with someone like my father, so..."

She doesn't finish her sentence and hides her face in her hands, at which point Derek asks with disdain:

"Then she decided to go after the idiot here so she wouldn't be alone."

Addison looks up immediately and tears smear her makeup, she stares at Derek with glassy eyes and states:

"No! I went after you because I loved you and I really wanted to get our marriage back together. I was going to tell you everything, but then I saw you with someone else and..."

"Oh so it's my fault for that too? You cheat on me and it's my fault, you move in with your lover and it's my fault, you lie to me and it's my fault."

"I'm not saying that. It's my fault and I regret it every day. I regret cheating on you, living with Mark, aborting the baby and leaving Seattle."

She explodes and feels her stomach sink as she realizes what she's just said. Derek widens his eyes and softens his tone as he speaks:

"Addison, I never told you to leave."

"No, you just told me you loved another woman!"

She speaks with a wry smile, but soon regrets it and dismisses it:

"That's not what we're talking about. Look, I'm sorry for everything I've done, I'm sorry for being na adulteress asshole and for taking the precious three months with the woman in your life."

She talks gesturing a lot and getting up from the bed. Addison walks towards the door, but Derek holds her back asking:

"Where are you going?"

"I'm going back to New York, don't worry I'm leaving Chris."

She prepares to open the door, but Derek holds her tighter, they look into each other's eyes and Derek pulls her in for a kiss. Addison immediately melts in her ex-husband's arms and pulls him even closer. They get lost in the kiss until Addison pushes him open and leaves the room. Derek follows her and takes her arm apologetically:

"Addie, I'm sorry it shouldn't have happened."

"No, you shouldn't. You don't have the right to say horrible things to me and kiss me like we don't have other people."

"I know and I'm sorry. I just don't want you to leave."

"But you're the one who sent me back. I don't want to stay here in horrible weather and ruin everyone's holiday."

"You won't. I can be civil about it."

"Based on the things you've told me, I highly doubt it."

"I was angry ok? But I want to put that in the past, what happened between you and Mark... Our son's happiness is more important than these things and that's why I want to leave it all behind ."

Derek speaks truthfully and Addison nods, she takes a deep breath and wipes away her tears before speaking:

"I'll be fine if you promise not to bring up these matters for the rest of the holiday."

"Promise."

Derek speaks truthfully again and Addison gives a slight smile before heading to the bathroom to compose himself. Minutes later Addison and Derek return to the living room where Nancy has Chris in her arms, she smiles at the redhead asking:

"Are you okay, Addie?"

"Uhm..."

Addison says and Derek frowns talking to his sister:

"So am I. Thanks for asking."

"Oh I wasn't worried about you."

Nancy talks teasingly and Derek makes a face. Addison just smiles at the brothers' dynamic.

Derek picks up his sleeping son in his arms and holds him to his chest, whispering apologies for scaring him. Addison strokes her son's curls and tries to comfort her ex:

"He's fine. It's been fine."

Derek just nods and Nancy watches them silently.

AAAA

The night arrives lively at the Shepherd family home with everyone gathered.

Playing with his son on the living room rug, Derek appears to have fully recovered from the incident with Mark. While the other family members don't even know what happened.

While the kids divide themselves between the living room and some of the bedrooms, Derek's three brothers-in-law watch TV.

In the kitchen, Carolyn makes the final arrangements for dinner with her three eldest daughters, who gossip:

"They still love each other."

She states Nancy to Kathleen who agrees:

"I have no doubt about it. They are AddisonandDerek, always have been and always will be."

"She cheated on him, Derek will never forgive that."

Liz retorts and Nancy states:

"If you had seen the two of them together today, the fight and the way they were after they worked it out... It looked like they were still married."

"Girls, let's get this over with. Derek has a girlfriend he loves dearly and Addie is fine with this Peter guy."

Carolyn speaks in annoyance and the three daughters look at each other before bursting into laughter. Carolyn stares at them shaking her head, but at that moment Addison and Amelia enter the room, ready to get more things for the dinner table. Seeing the scene, Amelia asks:

"What's so funny going on in this kitchen?"

"Just Mom treating us like teenagers."

"They act like."

Carolyn shrugs her shoulders and Addison smiles, feeling comfortable with the sisters.

It doesn't take long for dinner to be served, everyone gathers around the table and everything goes very well. The sisters talk nonstop, Carolyn scolds them, the kids and husbands laugh, Chris is spoiled by his grandmother, and Amelia makes unnecessary comments. Derek and Addison just watch in silence, taking in being there together again.

When dinner is over, everyone gathers in the living room, once again between conversations and small discussions. When it's just a few minutes to midnight, Derek approaches Addison inviting her to the back of the house with Chris, who is thankfully awake. The redhead accepts her ex-husband's invitation and the three head to the balcony.

The two sit on the swing and Derek puts his son on his lap, the little boy points to the snow that forms in the backyard and speaks slurred words. Derek watches his son, eyes twinkling, then addresses Addison:

"Thanks for staying."

"You do not have to thank me."

"It's been a good night."

Derek speaks with a smile. Addison nods and looks up at the sky as he says:

"That New Year's night I spent alone in the trailer, that's when I started thinking about leaving. You left me alone, just like my parents did when I was a kid and then when you came back... worst possible way."

"Addison..."

"I had planned to work over the holiday, but I was also hoping you wouldn't be so averse to spending time with me."

Addison laughs humorlessly and then turns to Derek, her eyes are a little glazed over and he feels a pang of guilt. Derek tucks a strand of her hair behind her ear and apologizes:

"I was hurt, Addie. I was hurt, frustrated and I'm sorry about that today."

"It's okay. I just wanted you to know how I felt."

She says with a shrug and at that moment Chris captures his father's attention by lifting himself on his lap and pinching his cheeks. Addison and Derek laugh at the attitude of their son who bursts out laughing.

As his son laughs, Derek looks at his watch and realizes it's a minute to midnight, so he puts na arm around Addison and pulls her close. Addison stares at Derek with a confused look and he smiles, hugs Chris to his chest and kisses his ex-wife's temple while whispering:

"Happy New Year, Addie."

"Happy New Year."

Addison speaks with a small smile and lets her head rest on his shoulder.

AAAAAAA

It only takes a few minutes for Addison, Derek and Chris to get back inside the house, as soon as they enter they receive endless hugs from all the family members.

Then Addison decrees it's time for her son to sleep and retreats to Derek's old room where his things are.

Just a few minutes later she hears a knock on the door and smiles as she sees Derek's face emerge from the small opening as she asks:

"Everything okay over here?"

"Uhm. I just got him dressed."

Addison speaks softly as she strokes her son's red hair. Derek smiles and sits on the bed stroking the baby's back, Chris looks at his father and smiles talking sleepily:

"Deek."

Derek smiles even wider and says in a childish voice:

"It's me, Deek, Daddy. Speak Daddy!"

Chris just laughs and snuggles into the pillow. Addison also laughs and adjusts the covers over her son, after which the two are silent and watch the baby fall asleep.

Minutes pass after Chris has fallen asleep and the two remain in the same positions, until Derek decides to break the silence:

"I'll let you rest."

"I don't want to disturb you. I can go to the couch and you can stay here with Chris."

"No way. I'll be fine on the couch."

Derek says and Addison nods with a soft smile. He prepares to speak again, but his cell phone rings and neither of them has to look at the display to see who is calling. Addison's smile fades and Derek stands up abruptly stating:

"I have to answer."

"OK."

That's all Addison says before seeing him leave the room, she then sinks into the bed and holds her son in her arms, letting out a weary sigh.

After a longer-than-expected conversation with Meredith, Derek returns to his old room. He slowly opens the door and smiles at the image of Addison and Chris sleeping together, he just watches them silently and then closes the door again and heads for the stairs.

AAAAAAA

Addison wakes up to a soft knock on the door, she rubs her eyes sleepily and allows entry. Derek opens the door smiling softly and says:

"Good morning. Mom is calling everyone for breakfast."

Addison smiles at the familiarity of those words and nods before speaking:

"Good Morning."

"Did you sleep well?"

"Yes and you?"

"Also. Mom's couch is more comfortable than it looks."

Derek states and winks at her, Addison smiles and starts to sit on the bed when he points surprising her:

"Do you remember this photo?"

She looks at the bedside table and smiles nodding. Derek also smiles and asks:

"Do you have the other copy?"

"I do. On one of our albums."

The word "ours" makes Derek blush and Addison averts her eyes back to the picture, picking up the frame and stating:

"We were so young."

"We were 26 years old. We were practically children."

Derek states in awe. Addison smiles at the photo once more, before placing it back on the table and asking:

"Do you wake Chris up while I get ready for the day?"

"He won't be scared of me?"

"Are you kidding? This boy loves you!"

Addison says making Derek smile widely, she smiles too and grabs her bag heading to the bathroom.

As Addison comes out of the bathroom, she hears Chris chuckling from downstairs, she goes downstairs and finds him sitting in the high chair while Derek gives him food by flying. Addison leans against the kitchen door watching the scene and Nancy approaches saying:

"He's as good as daddy."

"I never had any doubts that he would make a wonderful father."

Derek turns toward them and gives Addison a bright smile. Addison returns the smile and approaches her, she starts stroking her son's hair while praising Derek:

"You dressed him fast."

"He's na easy kid, isn't he Chris."

"Like the father."

Carolyn states proudly as she sets up the coffee. Addison smiles remembering how many times she's heard her ex-mother-in-law praising Derek and how much he supposedly was the best baby she ever had. Derek catches her gaze and gives her a smug smile before teasing:

"Obviously he's not easy because of his mother."

Addison soon retorts smiling:

"A pity if he doesn't have my bright personality."

Derek rolls his eyes and Carolyn frowns at the scene, while Nancy smiles even more convinced of her theory about the ex-couple.

AAAA

The rest of the morning is quiet, as is lunch, after which Addison starts packing up to leave. Holding Chris, Derek asks:

"Are you sure you don't want me to come back with you?"

"I do. It's easier for you to go straight back to Kathleen."

"Can I make you one more request?"

Derek asks with his glowing gaze and Addison just nods. He then asks:

"Will you take me to the airport tomorrow? Dylan offered, but I thought I'd spend a little more time with this little guy here."

Derek shakes Chris who laughs. Addison keeps smiling and states:

"We'll pick you up from Kathleen's house and accompany you, Doctor Shepherd."

"Thanks."

He speaks sincerely and Addison nods, refocusing on tidying up.

Shortly after, she says goodbye to the entire family and gets in her car, sharing one last look with Derek."

AAAA

Derek smiles with his suitcase over his shoulder as he approaches Addison's car. He gets in the vehicle and immediately pinches Chris's cheeks, saying:

"Daddy already missed you."

Chris repeats the last word and shows a teddy bear to Derek who smiles but complains to Addison:

"I'm leaving and he still hasn't called me daddy!"

Addison smiles and speaks without taking her eyes off the street:

"It's a word he hardly hears, it's normal."

"I will miss you."

Derek claims changing the subject entirely and Addison nods, secretly sharing the same sentiment.

At the airport, Addison holds Chris while Derek does the necessary things.

As soon as everything is ready, he approaches the two of them and says:

"I'll have to get on the plane."

"OK "

Addison speaks quietly and hands her son over to him. Derek holds the boy in front of him and says with teary eyes:

"Meeting you was the best thing that ever happened to me. Daddy will miss you terribly and soon he'll be here again."

Chris is much more interested in trying to get the papers his father is holding, but he continues:

"Daddy loves you very much and will never be away that long again."

He then kisses his son's forehead and hands him back to Addison who also has tears in her eyes. Derek approaches and kisses her forehead asking:

"Take care, Addie."

"You too."

"Thank you for everything."

Addison nods and Derek starts to walk away, she then shakes Chris and asks:

"Say goodbye to daddy."

Chris raises his little hand and waves to Derek saying:

"Daddy."

The smile that crosses Derek's face is the brightest Addison has ever seen. Tears overflow his eyes and he approaches again and kisses his son's cheek before saying:

"I love you."

After that he walks away again, turns his back and heads towards the departure gate.

Chris keeps waving and Addison just watches her ex-husband walk away, fighting back tears.

AAAA

This chapter was really long, I wrote it little by little during the week.

I brought in several Addek crumbs that were wonderful to write.

Always remembering that I own nothing.

Thanks for reading and sorry for any errors.