Disclaimer: I don't own it, just like it.

Fall… After Kaitlyn is back in school. Mark found Addison in the hospital.

"Addison. I need to talk to you."

"Are we going to have a normal conversation like two civil adults?"

"Things are never normal with us babe."

"This is why I can't talk to you." She started to walk away.

"No. Addison. Wait."

"What Mark?"

"Kathleen got arrested this morning."

"Oh my gosh. Why?."

"Why do you think?" They just looked at each other. "Can you watch Kaitlyn?"

"Yeah, yeah. Don't worry about her. She's taken care of."

"Thanks."

"Are you okay?"

"Yeah. Fine."

"Mark."

"We weren't together that long."

"She's the mother of your child. " He walked away.

Few days later. A small redheaded little girl ran down the hallway to Derek.

"Lilzilla!" He caught the girl in his arms and lifted her above his head, making her laugh. He planted a kiss on her forehead and held her.

"Hi!"

The interns had been watching from the desk. Izzie walked up to join the rest of them.

"Whose the kid?"

"Fifty says it's Shepherd's from New York."

"This is why we call you evil spawn." Meredith didn't believe that Derek had any more secrets.

"Hundred says it's McSteamy's." Alex was willing to take Cristina's bet.

"You're on. Sloan already has a love child." Addison walked up to them and put a chart in the rack. Izzie knew she would be able to answer their question.

"Dr. Montgomery?"

"Yes?"

"Do you know who Dr. Shepherd is holding?" Addison looked up and smiled.

"Lily!"

"That was no help." Addison walked over to Derek and Lily.

"My turn!" She held her arms out. Lily dove into Addison's arms. Addison hugged her tightly and kissed her head. "I missed you."

Alex still thought he was right.

"Sure looks like it's their kid."

"Derek wouldn't have hid that. We're engaged."

"He hid is wife."

"Addison wouldn't have hid it this long."

"I still think it's Sloan's."

"Why would Derek be that happy to see Mark's child?"

"They would have been very close when she was born so Derek would have gotten close to her too. No need to punish the child for what the father did. Besides, they've been buddy-buddy lately."

Derek's pager went off.

"I have to go. You got her?" Addison was still holding Lily.

"Yeah."

"See you later Lily."

"In a while crocodile." Derek and Addison laughed. Derek walked away. Addison carried Lily over to where the interns were. "I love you."

"I love you too."

"Can we go to the playground?"

"Later honey."

When they got to where the interns were Izzie started talking to Lily.

"Hi cutie. What's your name?"

"Lily." Cristina pushed for more information.

"More particularly, what's your last name?"

"Oh I want to hear this. What stories have you guys come up with in the five minutes Lily has been here?"

"Cristina and Alex have a bet. Alex says she's your kid with Dr. Shepherd. Cristina says she's Dr. Sloan's. Meredith says that Derek wouldn't have hid that from her because they're engaged. I don't know what to think, but I don't think she's yours."

"Enough with the verbal diarrhea. I want to know if I won a hundred bucks or not."

"Well Cristina, her last name is Sloan."

"Hand it over evil spawn." Addison's pager went off.

"I would love to stay and gossip with you all, but I have to get that. You five interested in babysitting since you seem to be not doing anything?" Of course Izzie was interested.

"Sure."

"Lily. Stay with Izzie and I'll come get you when I'm done seeing my patient, okay?"

"Okay." Addison walked away and Lilly began asking the interns questions. "What's your name?"

"My name is Izzie and this is Meredith." Cristina was more interested in corrupting the child.

"Let me do the introductions. See him right there?" Lily nodded. "He's evil spawn." Lily giggled.

"Evil spawn?"

"Yup. And that's bambi."

"Cristina, you're corrupting her."

Mark walked down the hallway with papers in his hand. Lily was trailing behind him. He found Addison.

"Addison. What am I going to do? I need her to start school, but there are all these papers and she needs a physical."

"Let me see." He handed them to her. " I can help with most of these. "So you have both the girls now. How are you going to take care of a four year old if you can barely take care of a fifteen year old?"

"She's four?"

"Yes. Where have you been for the past few months?"

"What am I going to do? I am a horrible father. Addison, I really need your help. Please. I don't know how to take care of a four year old."

"And I have any more experience than you do?"

"Come on. You're a pediatric surgeon. Just that right there gives you more experience than me. You want to be a mom. You are naturally the kind of person that makes a good mom. Isn't there some kind of maternal instinct?" Addison smiled and shook her head.

"Just because you admitted your problem and asked for help and because I know the girls are much better off with me helping than just you, I will help you."

"Thank you."

"But I'm not doing it for you."

"Chief gave me a day off to be with my children."

"That's good."

"What am I going to do with them?"

"Let's see you could pick your daughter up from school for once. You could play with your four year old who you haven't seen for a while."

"I don't know how."

"You were a kid not too long ago."

"Addison."

"Does Lily have a carseat?"

"No."

"Does Lily have a bed?"

"Crap."

"That's a bad word daddy."

"Yes it is."

"What kind of bed am I supposed to get?"

"You can get her a twin bed. Just get her a bedrail."

"Well, it's a good thing the chief gave you the day off to help me." He grinned.

"Mark. What if I don't want the day off?"

"Too late. Come on we have things to do."

A few nights later, Mark was trying his best to put Lily to bed. He managed to give her a bath without much of a problem. He was quickly learning that she was much more work than Kaitlyn.

"Lily. Put on pajamas." She glared at him and stomped her foot.

"No."

"Lily. Now."

"I not wearin pajamas."

"Fine. Get in bed without pajamas."

"No bed."

"Lillian Grace Sloan. Get in bed now. 1. 2." Lily climbed on her bed. She still didn't have clothes on or her hair brushed after her bath. "Lay down and I'll read you a book." Lily started crying.

"I'm not going to bed." Mark was frustrated. He was exhausted from his long day with the kids.

"Lily. Help me out here. I'm trying to be a good daddy. Please go to bed."

"No."

"What do you want?"

"I want Aunt Addie."

"You want Aunt Addie to put you to bed?"

"Yes."

"I'll see if she can come over." Mark called Addison, who was sitting on her bed peacefully reading before going to sleep.

"What do you need Mark?"

"That's a great way to answer your phone."

"I saw it was you and usually you need something."

"Let's go on a date."

"Wow. Change of the usual topic."

"How about dinner Friday night?"

"Okay."

"Good. Now will you please come over?"

"Why?"

"Because Lily says the only person who can put her to bed is her Aunt Addie."

"What is she even doing up? It's 9:30 and she's four."

"We've been arguing about going to bed for quite some time. I finally got her to take a bath, but she won't go to bed."

"Alright. I'll be there in 10 minutes." Addison walked in the house and right up to Lily's room. She was arguing with Mark still. When Addison walked in the room she smiled and ran to Addison. Addison picked her up.

"Hi Aunt Addie."

"Why don't you have clothes on?"

"I took a bath and I didn't want to do what Daddy says."

"You have to listen to Daddy. You have to be a good girl."

"But I want you."

"Crying and yelling and not doing what daddy says is not going to get you what you want. You should have changed into pajamas and gotten into bed and then asked daddy if you could call me to read you a bedtime story or something."

"Oh."

"Next time, that's what you need to do, okay?"

"Okay."

"Now, let's get some pajamas on." She sat Lily down and took pajamas out of her drawer. She helped Lily get dressed in her pink footie pajamas. Then Addison brushed her hair. "It's time to get in bed." Lily climbed into her bed.

"Aunt Addie?"

"What cutie?"

"Can you please hold me?"

"Since you asked so nicely, I'll lay with you for a little bit." Addison laid on the bed and Lily laid on top of her. Addison rubbed her back. Mark turned off the light and left. Fifteen minutes later Addison laid Lily, who had fallen asleep on the bed. She covered her up and left the room. She found Mark on the couch.

"I thought you might fall asleep too."

"I was that's why I got up. You have to be more controlling or something. You can't let a four year old control your life at home."

"She won't listen."

"Make her listen. Talk to her about the consequences or what would have happened if she acted differently. Give her time out. She has to learn."

"I feel bad for her. All she has is me. She needs a mother."

"She has me too. And Derek. She needs some discipline. Tough love. It's the only way she'll behave."

"I'll work on it. She listens to you so much better."

"She knows I mean it."

"In my house, my dad was the fun one and mom always meant business. I guess it's a natural thing."

"I'm not sure she's gotten much discipline from either of her parents."

"It's so hard."

"I know, but you have to try. For Lily."

"I never planned on becoming a father so early in life. With Kaitlyn, it was good. Elizabeth was there. Kaitlyn and I had a different relationship. She's so laid back and goes with the flow, but Lily."

"Things don't always go as planned. I know. I'm here. I'll help you with almost anything. Really. I would appreciate a little more notice."

"Sorry. I didn't plan on calling you."

"I know. If it's bedtime you are having trouble with, I'll come over and help with bedtime whenever I can until it gets easier. Tell me what you need."

"She's little. I don't do little well. Kaitlyn I can do, but not four and not younger. I think at those ages the moms do most of the work. It doesn't come with paternal instinct."

"Maybe not, but it's something you can learn to do. What do you want help with? What's the hardest thing at the moment?"

"Bath and bed. She can be very difficult at that time."

"She's tired. She's getting her way because you give in easily because you're tired. You need to get on a good schedule and stick to it. I'll help. What time is she going to bed now?"

"Whenever I can get her in bed."

"I'll come over around 7:30 as long as I'm not working and we can start to get her on a good schedule. It's past ten now and she hasn't been asleep long. It's not good for her. She's waking up early and not taking a nap. She needs to go to bed earlier. Where's Kaitlyn?"

"Probably in her room."

"She needs a bedtime too if she's staying up late."

"I vote you work on that."

"Tonight and only tonight. From now on, you have to be the disciplinarian. You're the one who's living with them." Addison walked upstairs, knocked on the door, and went into Kaitlyn's room. "Time to get ready for bed."

"I'm 15. I don't need a bedtime."

You have to get up for school at 6:30. It's currently almost 10:30. That means if you go to sleep at this moment you'll get 8 hours of sleep, which is the absolute minimum you should be getting. If you still have homework to do, maybe you should be starting your homework earlier in the evening."

"I'm not a baby. I can choose when I go to bed."

"You can. If you choose responsibly. If you're staying up too late, taking advantage of being on your own, you're going to need a bedtime. Tonight, I'm saying go to bed."

"Fine. Lily just went to bed."

"Guess what. Starting tomorrow Lily will be in bed by 8:30 if I can help it so she will have been in bed for two hours by now. You need sleep."

"Alright. I'm getting ready for bed."

"Good. Lily's going to be learning a thing or two about who's boss around here. I think if you continue talking back, you'll be joining her."

"I'm not…" Addison gave her a look.

"I'll be back to make sure you're in bed in fifteen minutes."

"Okay." Addison opened Kaitlyn's door. The room was dark and everything was put away. Addison walked over to the bed using the light coming from the hallway.

"Thank you. If you listen to us, Lily will probably follow the good example you are setting and listen as well. Show us your good behavior. You can't start acting out now that we also have a four year old to take care of. You have to be the good one."

"I don't like this." She yawned.

"I know, but see you're yawning so I know you're tired."

"My brain is just deprived of oxygen."

"Well, miss smarty pants, that generally happens when you are tired. Goodnight." She kissed Kaitlyn's forehead.

"Goodnight."

The next night Addison came in the house a little before 7:30. Lily was running around screaming. Kaitlyn had the tv on loud.

"Hi."

"HI!"

"Where's your daddy?"

"In the kitchen."

"It's getting close to quiet time. How about you go pick out a couple of books for us to read before bed tonight?"

"Okay." She ran off.

"No running and no screaming."

"Okay." Addison turned to Kaitlyn.

"Is your homework done?"

"No."

"Then you shouldn't be watching tv. Go get to work on it. You're not staying up past 10 tonight."

"But."

"Nope. No arguments. I heard you were very tired this morning. You're going to bed at 10."

"Fine." She started to walk away.

"What did I say about talking back?"

"Don't do it."

"Yeah. Let's work on not doing it."

"I'm going to my room to do my homework."

"That was a better tone. Thank you." Kaitlyn went upstairs and Addison went into the kitchen where Mark was cleaning. "What happened in here?"

"Lily accidentally spilled the rest of the lasagna including the glass dish. I'm trying to clean it. It's like chaos tonight."

"I can tell."

"They're quiet now. What did you do?"

"Lily's picking out bedtime books and Kaitlyn's doing her homework. You have to have a little more control over them. Don't let Kaitlyn talk back to you either."

"We were doing good until after dinner."

"I believe it. It's when they're getting tired that they're bad."

"Is it bathtime?"

"It should be, but I'll do bath and you can finish cleaning in here." Addison went back out to the living room and Lily was walking down the stairs with her books.

"I got some books."

"Okay. It's time for a bath."

"No. I want to read. You told me to get books."

"We are going to read after your bath. And you need to start saying no less. When we tell you to do something you need to do it."

"But I want to read."

"No. We are going upstairs. You can put those books on your bed. We'll read them as soon as you are finished with your bath. Let's go. I don't want to hear no out of your mouth again tonight." Lily started quietly walking up the stairs. Addison followed her. Lily went into her room and put the books on the bed. She put her arms up to Addison. "You don't need to be held right now. Into the bathroom." They went in and Addison started filling the tub as Lily got undressed. Addison gave her a bath. She didn't want to play long so the bath was quick. Lily got out and Addison wrapped her in a towel.

"Can you hold me please?" Addison picked her up and carried her into her room. Mark met them there. Addison put Lily down.

"Now Daddy is going to get you dressed, read to you, and put you in bed. You need to listen to him." Addison waited for Mark downstairs. He came down half an hour later.

"I don't think that went too bad."

"Definitely better than last night." Mark sat down on the couch next to her.

"So about that date tomorrow night. You're still going on a date with me right?"

"Actually, I changed my mind."

"Addison. I love you. I've loved you for a while. I want to spend time with you. You're beautiful, smart, funny. You love my girls like they are your own. Please. I'm begging you. Just one date."

"I wasn't saying no. But it's nice to hear you beg. All I was going to say was that I have one condition. I'll go on that date with you, if you put Lily to bed. You're not leaving that to your babysitter."

"Ooo I need a babysitter." Mark quietly thought to himself.