Disclaimer: I do not own Grey's Anatomy.

A/N: Believe it or not, this fic is actually based on a dream I had a few nights ago. I couldn't get it out of my head, so I decided to turn it into this oneshot. I know it's kind of weird, but let me assure that it makes more sense than my dream. Long story short, my dream was that Addison and Derek were at the beach swimming in freezing water, when a tsunami-sized wave came and froze above them. Addison then saw a dying tree and convinced Mark to perform surgery on the tree, which, I should mention, was completely successful and later the tree had baby trees, and then they went to the hospital. Addison talked to a semi-lucid Ellis Grey, while Mark talked with Izzie and Alex about the death of George's father. Suddenly Derek showed up with Meredith, and Addison talked to him, before going off to find Mark. Mark and Addison had this conversation, and somehow I learned that I wasn't the daughter of Derek and Addison (which I had thought that I was), I was really the daughter of Addison and Mark. And then my real-life friend showed up and told me that we should stop going to school and become truckers, which is what we did.

I'm really an Addek person and if not Addek, then Addex, but ever since this dream I've been craving Maddison. Obviously their marriage wasn't perfect, and so perhaps Maddison is great too! Anyway, despite my long boring story of my dream, which I'm amazed by how much I remember, this is my fic. I hope you enjoy it…and please, please, please review!

Memories Long Lost

"Derek, do you remember two years ago when we went to Hawaii? It was really cold out, and the water was rough, but I insisted that we go in anyhow, and so we did. You kept grumbling about how cold everything was and told me that you wouldn't have come if you'd known that you would be subjected to this sort of torture." Last night, for some reason, as she took a shower in cold water because there was a problem with the hot water, the memory had come to her. It disturbed her that she felt as if she was missing part of it, though, and so she had decided to ask for clarification from Derek.

"Addison, what are you talking about?" Derek asked, confused.

She tilted her head, lost in thought. What was it about the memory that wasn't quite right? "You don't remember?" she questioned. "We decided to take a trip to Hawaii, and then Mark decided to come along because he got asked for a consult at a local hotel. He only got to the beach one day, I think, but that was the best day of the trip because everything seemed so perfect…you don't remember this, Derek?"

"It's not that I don't remember it, Addison," he said, "it's that you're remembering it wrong. We had that trip to Hawaii planned for ages, and then I got asked for a consult, and I took it without telling you. When you learned you were absolutely livid, and so Mark decided to take his vacation in Hawaii so that you wouldn't have to spend the whole time alone. I only got to the beach one day, not Mark, but it was okay because we were happy anyhow."

Memories rearranged themselves in Addison's head, and she knew that he was telling the truth. "We weren't happy, Derek," Addison told him, her voice flat and emotionless. Before he could protest, Addison turned around and walked away, afraid that at any moment she would break down in tears. She had to find Mark, had to verify that what Derek was saying was true, though she wasn't sure on why she needed to so badly.

Her shift was over, and Mark wasn't working today, so Addison drove to the hotel, pushed three, and knocked on Mark's door. After a moment Mark appeared at the door, holding a book, and looking shocked to see her. "Addison—" he began, but Addison cut him off.

"We have to talk, Mark." She barged past him into the room, and he stared at her, stunned. She had not wanted to have much to do with him, and she had wanted him to move back to New York. Essentially, she had wanted to sever ties with him, to pretend that he didn't exist, to pretend that they hadn't been best friends for years. He couldn't understand why the sudden change, but he was willing to give it a shot, since he missed her more than he would let on.

Addison sat down on Mark's bed, and he sat next to her, keeping a respectable distance between them. "Are you okay?" he asked her, noticing that she seemed on the verge of tears.

"In Hawaii, two years ago, was it Derek who spent the whole trip at the hospital?" The words came out quickly, and she felt herself breathing too fast. She wasn't sure what the response she was looking for was, wasn't sure if she wanted to admit that she and Derek hadn't been happy for years before their divorce, wasn't sure if she wanted to admit that perhaps it hadn't been a mistake between her and Mark.

"Yeah," said Mark lightly, not understanding the importance of the question. "While Derek spent the whole time at the hospital doing surgery, we spent the whole vacation on the beach and visiting touristy places. Derek only made it to the beach one day, but at least that meant he didn't have to be submitted to artic temperature water."

A tear slid down Addison's face, and she wiped it away quickly. "You remember that?" she whispered.

"How could I forget?" he questioned. He started to laugh, but stopped quickly when he saw the look on Addison's face. It was a look that he had hoped to never see again—a look that said clearly that she thought she could never be happy again. "Addison, that water was cold! It would take more than a few years to make me forget that…why you were so insistent that we swim was beyond me," he said, trying to cheer her up.

"You remember," she repeated softly.

"Well, if it's any consolation, it was the best day of my trip," Mark told her. "Remember how I kept telling you that the waves were going to freeze while we were in the water, and we'd die of hypothermia?" Addison nodded and smiled slightly, before quickly wiping away another tear. "Addie, am I missing something?" he asked, worried. "Did something happen?"

"I thought it was Derek. I thought all of those things you just said…I thought I had done them with Derek. I wanted to believe that Derek and I were happy so badly, so badly…" she said, her voice ragged and uneven, yet somehow emotionless. "And it was you. You were the one who made me happy. Mark, after we were together, why did you still sleep around?"

Mark had never expected this to come up the way it just had. He had expected Addison to yell at him, and to tell him he was an awful person, and to storm about, and perhaps to cry, and definitely to ignore him for a while; he had not expected for her to just look at him with that look that said she could never be happy. And his answer, he knew, was an unsatisfactory one, an answer that he thought she'd never believe, even though it was the truth. "I was afraid," he admitted, looking her straight in the eyes.

"I was afraid that I'd mess it up with you, that we would never be happy the way you and Derek used to be. I was afraid that we'd make the same mistakes that you and Derek made, that we'd become lazy and successful and not try any more, and I didn't want that to happen, so I slept with others. I figured, perhaps it would be better for me to be a jerk than for us to slowly grow apart. I watched what happened with you and Derek, and I watched how broken and upset you were, while he didn't even notice anything was wrong. I didn't want that to become us…I didn't want us to become like that. And I'm sorry, Addie, I'm so sorry." Mark looked at Addison, realizing that his words had only caused her to start crying.

Addison leaned towards Mark, seeking comfort, and he scooted closer to her on the bed, and hugged her. He wasn't sure if she was clinging to him, or he was clinging to her, but either way they were desperate to be near each other. "Shhhh, Addie, it's okay," he whispered into her hair.

After a few minutes Addison had calmed down, and she sat with hear head leaning against Mark's shoulder, his arm protectively around her. "Mark?" she asked.

"Yeah?"

"Thanks for keeping me company in Hawaii." Addison smiled up at him. "It means a lot to me."

Mark looked away, unsure how to take this compliment. "Well, what are friends for?" he eventually responded, clearly embarrassed.

Addison turned to face Mark, and kissed him softly, both amazed by the intensity of the kiss. When they stopped, Mark looked at Addison questioningly, surprised by what they had just done. He loved Addie so much, and he wanted to be with her, but he also wanted to be sure that she hadn't just kissed him because she was lonely, which had been the reason last time. "Mark, this time I'm perfectly sober," she informed him, causing them both to laugh.

"Are you sure I'm not just again acting as a substitution for Derek?" he asked bitterly. Addison took a moment before she answered, thinking it over. Was she really over Derek? Was she really willing to admit that her marriage was over, that it hadn't even been happy for the last few years? And, most importantly, was she ready to get involved in another relationship, especially one with her best friend?

"I'm sure," Addison said, looking him in the eyes. "I…we weren't happy, Derek and I, but that time I slept with you in New York, it wasn't a mistake, exactly. I loved you, and I thought that loved Derek, and so when presented with the choice, and after you had slept with Charlene the peds nurse, I decided to try and fix my marriage. I was hurt, and you can't really blame me, Mark, for wanting to fix what I had lost. When I called you to Seattle that first time, it wasn't just so that I wouldn't be alone…it's because I needed you, Mark. I needed you to be there for me, and I knew you would be, even if I hurt you, even if I acted like a jerk."

Mark wasn't sure if he wanted to know the answer, but he had to know. "So I mean something to you?" he asked timidly. He wasn't sure the moment when it had happened, but he had been in love with Addison since sometime before Derek married her.

"Yeah," Addison said simply, allowing both of them to be happy for this one moment.