A/N:

Don't get me wrong, I like MerDer and I will probably always ship it. But the way Mark flirts with Meredith in Season 2 Episode 18 "Yesterday" is just so good. So here's my first attempt ate a Mermark story. I start with what is given to us in "Yesterday" but quickly diverge off that path! This is a short chapter but I am just getting started. Hopefully longer ones are on there way!

I am always open to suggestions so please review! Enjoy!

(I don't own Grey's Anatomy, I'm borrowing characters and a few ideas. Italics are taken from the show.)

She stood looking over her patient's charts, her thoughts focused on the fact that COPD was going to make the case a bit more challenging.

"Invasive non-small cell with a history of COPD? The guy's pretty much a goner, huh?" came a male voice. She turned slightly to her left, looking up to see the handsome face that matched the voice. She smiled as she processed him.

"Sensitivity. I like that in a stranger. Are you new here?" she questioned. He had to be a medical professional, the way he read the chart so quickly and knew how COPD would be an added difficulty.

"Visiting. Confounded by all the rain and it's only my first day in town." He grinned. She took the chart and walked down the counter a little ways. She had to continue her work before she got behind. The last thing she needed right now was to anger her superiors. Staying on top of her workload was also a distraction. A distraction from begging Derek to choose her.

"You get used to it" she said simply, with a nonchalant shrug of her shoulders. He followed her down the counter circling to her other side, a flirtatious grin across his face.

"It makes me want to stay in bed all day." He mention, ambiguously. She looked at him, taken back by the underlying meaning. Her heart rate increased at the thought of being with him and not Derek. And she was almost okay with the idea.

"We just met and already you're talking about bed. Not very subtle" She countered, liking the straightforward approach,

"Subtle has never been my strong suit" He said. "So, do you ever go out with co-workers?"

She felt her insides twist, a little adrenaline pushing through her body. The last time she went out with a co-worker, he broke her heart. It was better that she not repeat that move. She paused, smiling before answering.

"I um make it a rule not to" She said, fighting over the part of her that desperately wanted to go out with him, to see what other fish were in the sea.

He just smirked. "Then I am so glad that I don't work here".

Her heart sped up again. This could go so many ways now. He is not her coworker so she could go out once and never see him again. Or she could actually consider going out more than once and it would never get messy at her workplace again. "Are you hitting on me? In a hospital?"

"Would that be wrong?" He asked with a feigned innocence. She could only smile and shake her head. This could be something she like. He could be someone she liked. And she wouldn't have to worry about working with his wife everyday, if he had one. Hopefully not, she thought. It was time to give it a shot.

"Meredith" she introduced offering her hand with a set smile. He grasped it with confidence and strength. But before he could say anything else, or introduce himself, Derek punched him. The man went down, hurriedly placing a hand over his injured face. Derek shook out his hand, a jealous and angry look in his eyes. "What the hell was that?" Meredith asked, snapping out of her flirtatious fog. Since when did Derek, the man who lied to her about his wife, Addison, and then chose his wife over Meredith, get jealous of a single interaction with a stranger?

"That was Mark" Derek grimaced, his hand still in pain. Mark? As in the man who slept with Addison? What were the odds that of all the hot men to hit on Meredith it had to be Mark Sloan? She looked at the man still sitting on the floor, shocked. She then looked at Derek and shook her head.

"Why did you do that?" Meredith demanded.

"Why did I-? He was asking you out!" Derek replied, exasperated. This infuriated Meredith. Derek made a point of choosing Addison but when it came down to Mark, his only concern was Meredith. While she was overjoyed at the prospects of his care, she also found it increasingly more annoying that he was acting in whichever way suited him. Addison shows up? It benefited him to be with her. Meredith asks him to chose her? Still beneficial to be with his estranged wife. Mark flirts with Meredith? Suddenly it is a priority to protect Meredith, while Addison was just a few feet away from them.

"And why would you care, Dr. Shepherd? We aren't dating anymore, you're happily married. So why do you have to care?" Meredith asked, crossing her arms. Derek looked her in the eyes.

"You were going to go out with him, weren't you?" Derek accused. "He's a serial dater, Mer-"

"It's Dr. Grey" Meredith snapped, her anger rising. He was giving too many mixed signals. "Be a professional adult, Dr. Shepherd. Excuse me while I help this man." She turned and rushed over to Mark who had since stood and was leaning against the counter. He grinned at her.

"Feisty. I like that in a stranger" he turned her words against her. She just shook her head and began leading him to an exam room.

"Let's go get you fixed up, I will take excellent care of you" Meredith put her arm around him, making an effort to avoid Derek's eyes.

"I am sure you will, Dr. Grey" Mark replied, adding emphasis on the doctor.