Spoilers: Definitely "Duet", and maybe "Critical Mass" as well…

Disclaimer: Stargate Atlantis isn't mine…if it was, Carson's uniform would consist of a kilt and not much else… : )

Note: I never followed SGA in sequence, and "Duet" was actually one of the first episodes I ever watched. To this day, it's one of my favourite episodes for numerous reasons, but particularly for the romance between Beckett and Cadman. Still, their romance is a bit of a mystery to me, so I tried to explore it in this fic (I'll be heading back to Sparky soon, no worries : )). Hope it works, and once again, comments and criticism always appreciated!

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She makes him smile.

Not that it's such a tough feat to achieve, or that he's known for solemnity, for being grim. It's simply that in his current location, he hasn't really had that many chances to smile. Hell, he hasn't had many chances to do much except worry and panic and then worry some more. Routine is unheard of in the Pegasus Galaxy, and it used to be that not a day went by where he wouldn't question his judgement about joining the Atlantis expedition.

But then he met Laura Cadman, albeit a brief meeting before she was taken from him momentarily, but it was enough. Enough to let him see a glimpse of the down-to-earth, entertaining woman that she was. Enough to make him grin at her jibes towards Rodney.

Enough to like her for it, too.

Although it certainly isn't difficult to insult the Canadian scientist—it's become a sort of sport amongst the expedition—there had been something in the way she had managed to make the man sputter that had tugged at the corners of his lips. There she was, a new recruit, and already she had Rodney pinned down to a tee. And already she could get his hackles up as easily as any hardened Atlantean.

And if that didn't foster respect for Lieutenant Cadman then her stay in Rodney's head for those few days—and her remarkable ability to remain sane throughout the entire experience—certainly had garnered his admiration. He highly doubts he would have been so easygoing about such an experience, particularly since he really has no desire whatsoever to get into that particular man's head.

But she just laughs about it, finds it quite amusing that Rodney still can't look her in the eye even thought its been months. And he finds that he ends up laughing right along with her as she reminisces about the disastrous dinner date with Katie the botanist, or the moment in the lab when she was masquerading as Rodney and he had said, unknowingly, that he thought her to be a lovely woman.

They even laugh about the kiss—the kiss that she instigated even though it was Rodney's hands on his lab coat and Rodney's mouth on his own. Although when they mention that particular incident, he can't help but go a little more than red at the thought. When she sees his cheeks brighten, she giggles a little more, reassuring him that if she ever gets stuck in another man's body, she'll try to hold herself back.

He'll usually respond with an "I bloody hope so", but there's never any threat behind his words, and she'll always grin at him in the sweetest way, so lightheartedly that he cannot help but grin right back. It's in those quiet moments where he marvels at how easily they get along, how comfortable they are around each other, how simple it is to talk to her. They are two very different people, yet somehow, beyond all reasoning that he can come up with, they seem to work.

Sometimes when the research in his lab is in a lull, or when—on those rare, rare occasions—he isn't needed to cure an alien virus or remove a projectile from some unfortunate soldier, he finds himself looking back on all of those little moments they have created. He's always been a sentimental old codger, always been a real softie as his mum used to say, and though he tries his best to hide it, half of the base seems to have discovered that side to him. A few tease him about it, a few have taken advantage of it, but nobody holds it against him. And nobody faults him for it either.

So he'll let himself drift during those precious moments of peace, remembering the first time they ever really had a chat, just after he had released her from the infirmary, when her torture of being apart of Rodney McKay was finally finished. It had been the end of his shift when he discharged her, and Laura had ever so casually suggested grabbing some dinner together. Over a helping of mystery meat and flavourless mashed potatoes, they had talked about everything under the sun, from family to work to the strange inner workings of the people of Atlantis. In the process, they managed to avoid the entire 'kiss a la Rodney's body' discussion, and instead had a rather pleasant time.

Having been raised to be a gentleman, he had dutifully escorted her back to her rooms, keeping a close eye on her to make sure she was medically fit to be out of the infirmary. Ever the doctor, he had been too busy studying the pallor of her skin to realize that she had not gone straight through her door when it opened but had inched closer to him.

As he was coming to the conclusion that his patient was, in fact, quite healthy, her hands had gripped his head and brought his lips down to hers in a similar fashion to the kiss they had—sort of—shared before. But this time it was her own soft lips parting briefly beneath his own, her definitively feminine scent lingering in his nose, and her slim, explicitly female body pressed close to his.

Too shocked to speak, he had gaped at her as she pulled away. She had arched a brow, grinning at him.

"Now that," She had announced, "was a little more like it."

Then, with a laughing pat on his cheek, she had disappeared into her room, leaving a rather stunned chief medical officer standing outside her door as his usually alert mind took its dear time processing the event.

But as the shock filtered out of his system, the most wonderful thing happened. A smile had begun to break across his face, an honest-to-god, muscle-hurting, face-straining grin that had remained there as he started the long walk to his own quarters. It had stayed planted on his lips even as his head hit the pillow, and for the first time in a long while, he had awoken with the hints of a grin still lingering on his face.

Her ability to create that kind of effect on him is rather amazing and yet touching too. Somehow she always manages to make him smile, even when he starts to feel as though he cannot keep up with the stressful pace of Atlantis any longer. But she does more than that too—she keeps him steady, keeps him from going overboard with worrying and fretting over situations. They are different, like day and night, but he believes that their differences balance each other out, that being so different from each other is what makes their relationship work so well.

Where he tends to indulge in moments of near-breakdown, she is steadfast in her ways, hardly batting an eyelash even when people start muttering about the city's final bells tolling once more. Where he pays attention to detail, takes everything into consideration before forming an answer or an idea, she just simply takes a step back and looks at the whole picture, then goes from there.

Still there are differences that baffle him too, ones that shouldn't really correlate together, yet they don't seem to pose a problem. She is, after all, a soldier and is at home in fatigues, feels comfortable carrying a gun, keeps her head cool in a fight, and specializes in explosive materials. He is a medical man, completely at home in a lab coat, knows each and every organ in the human body inside and out, and who would much rather be wielding a scalpel than any sort of explosive material any day.

Yet she finds his work fascinating, enjoys hearing his tales from medical school, listens attentively if he feels a need to talk about the latest medical breakthrough he's had with his research. And in turn, he finds it remarkably easy to listen to her stories about the army, can ask competent questions about her training, looks forward to hearing her stories about her missions off-world.

They shouldn't work, but they do, and he can't help but marvel at the fact that apparently physics did get it right after all—though he'd never admit that to Rodney for fear of skyrocketing the man's ego further—that opposites really do attract.

There are times when he worries that he might be too old for her, that she might look at him one day, see the gap and decide that she wants someone closer to her age. Someone who isn't so different, someone who understands a little more of her life. He worries, but he makes sure to push those thoughts far aside. The future is always changing with each second that ticks by, particularly in this city, and he wants to enjoy the moments that are being granted to him. If this expedition has taught him one thing, its that savoring the ups of life will help to ease the painful fall of the downs.

So when he hears footsteps echoing through the quiet medical lab, he puts away the report he was reading and quickly shrugs out of his signature lab coat.

"Hey, you're not still working are you?" Laura asks, blond hair framing her concerned features when she sees him bent over the computer. Dressed in a simple blue shirt and brown slacks, she seems to radiate vibrancy and he finds himself once again faced with the beautiful portrait that is Lieutenant Cadman. He also finds that the computers aren't turning off fast enough for his liking either.

"Not anymore, love, " He replies, waiting for the screen to flicker off. "So what's on our agenda for tonight?"

She crosses her arms, a slight grin playing across her pretty features. "Well, I figure dinner is always a must, even though I've been warned not to try the dessert. And then I managed to wangle the DVD player from Dr. Biro for the night, if you're up for a movie or two."

"How on earth did you manage that feat?" He looks to her with surprise. The ruddy DVD player is always getting claimed by someone or another—particularly by a certain Lieutenant Colonel—and Elizabeth had finally set up a waiting list for it, which, last he heard, went at least into the end of next month.

She sends him a sly look. "Girl's poker night, of course. I happen to be a great bluffer."

"Remind me never to accept a poker challenge from you. I've never been good at keeping a straight face, particularly when I'm losing."

"Somehow that doesn't surprise me, Carson," She teases. "Now come on, let's go grab some leftovers before they get too cold."

The computer finally shuts off, and he offers his arm to her—an offer that she gladly accepts, winding her arm around his as they set off down the quiet corridors of the Ancient city that they both are calling home.

He knows that one day in the future she will be boarding the Daedelus once again, on her way back to Earth, and he can't help but worry about how he's going to be able to say good-bye to the woman who has made his stay in Atlantis all that much more bearable. He worries of course, but he decides that tonight is not a night to let his thoughts get the better of him.

Tonight he will talk with a woman who intrigues him and puzzles him and makes him chuckle all in one go. He will be able to lose himself in her embrace, hold her close as they inevitably both doze off during the movie that they will most likely spend a few minutes arguing over beforehand.

Most importantly though, he will feel the muscles in his jaw ache as he laughs and grins, and smiles softly at the truly lovely young lady who has brought such occurrences so frequently back into his life.

So when she looks up to him, grinning and reminding him for all the world of a delighted pixie, he lets the smile that was in his eyes reach his mouth.

True, they may be opposites in many ways, they may be from separate worlds, different backgrounds. They may not always agree on movies, particularly when he feels the patriotic urge to indulge in a little Braveheart, but there is one thing that stops him from questioning the 'why?' aspect of their relationship too deeply. One thing that, though seemingly insignificant to some, makes him stop in his doubts and bring her closer to his side.

It's not because she's beautiful, intelligent, or that she somehow finds an old, overly fretful doctor attractive—though those qualities do help.

No, when it comes down to the basics, it's simple.

It's all because, even when the world is falling apart at his very feet, when evil lurks just around the bend, she can somehow—beyond all logic, all reason—truly make him smile.

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