AUTHOR'S NOTES: If you don't watch 'Fragile Balance' and read 'The Difference Between Men and Boys' first, this story is going to make zero sense.

Certainties

Some things never change.

"I didn't do all that well in Chemistry last time I was taking exams," Jack complained. "So I think having to go through it a second time is unfair." He was going through his notes for chem finals tomorrow. "I'll only fail again."

"Life didn't come with a 'fair' sticker on the package, sir,"came the response from the girl lying on his bed. "And you won't fail."

He glanced at her and frowned at her use of his old mode of address. She was lying on her back, staring up at the ceiling, with her legs resting up against the wall and her feet on his poster of the X-305 no less – a 'birthday' present from 'Uncle' George.

"Get your feet off the poster, Carter!" The pointed use of her surname got her attention, as he'd intended it to do. She stared at him in surprise for a moment, before she lifted her feet from the poster and flopped them down on the mattress.

"Did I call you 'sir' again?"

"Yes."

"Damn." She propped her head up on her elbow, her gaze internally focused for a few seconds as she replayed the conversation in her head. Then she looked up at him, in all seriousness. "This could be a problem."

"This could be a problem?" Jack snorted. Smart as she was, she could occasionally be incredibly dense about some things. He put down his pen and pushed his chair back, stretching his legs out under the table. He'd been at the equations for nearly an hour now. It was time to take a study break. And address this issue before it got them both into trouble. "Sam, you've been calling me by name for the last two years – why are you suddenly starting to revert now?"

In the early days, they'd found it easier to think of each other in terms that they'd been careful to avoid the six years before that. These days Jack thought of Lieutenant Colonel Sam Carter as 'Carter', and his schoolmate Sam Carter as 'Sam'. He'd thought she was doing the same, so the relapse was worrying.

She traced patterns on the bedspread, chewing on her lower lip, and he waited for her to respond.

"You look more like him, now. Sound more like him."

"Which means...?" He knew he had an ugly note in his voice – the old fear of being inferior to 'that' Jack O'Neill. The older one. The original. He heard it in his voice and he saw it in her eyes as she looked up at him, startled.

"It's just instinct," she responded, now defensive. "Old habits coming out."

"So the last two years have been, what? Chopped liver?"

Sam glared at him. "No. But sometimes when I'm not looking at you, I forget. It's just habit."

"It's been two years!"

"And it was six years before that!" Her voice crackled with annoyance. "It was one mistake, Jack. And a completely unconscious one at that!"

"You'd better be careful, that you don't 'unconsciously' call me 'sir' in public, then," he rapped out, harsher than he intended.

Her mouth drew together, "I'll be sure to do that."

They stared at each other for a long moment before she got up, brushing non-existant dust specks off her t-shirt. "I think I'll go to bed," she said at last.

"You mean you'll read that journal in bed for the next two hours?" He said sarcastically.

"I mean I won't sit here, and take this kind of crap from you, Jack!" She headed for the door, but he was faster and got between her and the exit. "If you're not going to be civil, I'm not going to talk to you," she told him, with the calm detachment he hated seeing in her. It reminded him too vividly of 'Major Sam Carter', watching every word, look, and touch between them, lest some hint of impropriety be reported back to their superiors.

Huh. Maybe they did have too much history to make a future of it.

But Jack had never been one to take the system lying down like a good little subordinate – and he knew only too well the streak of recklessness in Sam Carter.

"I'll be civil if you stop calling me by a title that isn't mine anymore."

She threw her hands up, "For crying out loud, Jack, it was once. Count it on your fingers – permission to use your toes if necessary! Once. Completely unconscious and totally unsuspecting at that! Why are you getting so uptight about it?"

"Because I'm not him!" He snapped back, incensed that she had to ask at all. "I'm not him – pushing fifty and wanting a woman who might as well be as distant as the moon for all the interest she shows in me!"

She gaped at him, her jaw dropping in amazement. "You...him...?"

"Come on, Sam!" Jack said, shortly, aware that he'd betrayed not only his own secrets, but the secrets of his other self – the man who had taken Jack's life. "You had to be aware..."

The flush would have been cute under different circumstances. "Well, yes, but not...not like that..." And what she didn't say was that the intensity he'd always felt but never shown made all the difference. As long as 'Colonel Jack O'Neill' kept his distance and was charming, friendly, and lightly flirtatious, 'Major Sam Carter' had never had to deal with 'Jack' – only with 'the Colonel'. The parameters were known and accounted for – no unknown variables in the equation.

And jeeze, he'd been hanging around Sam way too long if he was starting to think in mathematical and scientific terms now. This whole education thing was so not good.

"So as long as you could ignore me, it was okay, huh? As long as I kept everything nice and neat and orderly – for your sake – you were okay with feeling feelings?"

"No," she said, but her tone of voice had the quality of someone trying to hold onto a slippery belief.

"Fuck," he said with pithy frustration. He'd always known that Carter didn't let herself see him as a man. Not really. This just proved it.

The grimace which crossed her expressive face would have been comical under any other circumstances. "Look, it's been two years. We're not who we were – you know that as well as I do. We don't look at each other the same."

His frankly admiring gaze over her figure earned him a glare. "What?"

"I meant...oh, you know what I meant."

"And?"

"So it's not...things aren't the same...you can't cast her behaviour in my face anymore!"

"It was your behaviour, too."

"And what kind of choice did I have?" Sam demanded. "What kind of options were we ever given? They put us in a situation where we had very little choice but to care and then wouldn't give us any way out of it!"

He stared her down. "We have options now."

"We have options," she reminded him. "They don't."

"We aren't them. And the thing about options is that you take them."

She stared at him. "Is that what this is about? You're sulking..."

"I do not sulk!"

"You do sulk," she retorted. "You did then and you do now!" She calmed herself, exerting visible effort to do so. Once again, the trinium of her self-control imposed the limits of her behaviour – and Jack scowled. "Look, it's not that..." Sam paused and flushed. "It's not that..."

"It's not what...?"

"It'snotthatyou'renotattractive," she said very quickly and all at once, as if it would make it easier to slur it all together. "It's just..." Sam bit her lip. "Old habits."

He wasn't going to take that. "You've already used that excuse once, you can't use it a second time."

She glared at him and, abruptly in a better frame of mind, he grinned. There was something about knowing you hadn't lost 'it' that made a man feel distinctly better about himself. "Tell you what, Sam," he said, cockily. "You go with me to the prom – and don't think I don't know you've already gotten a dozen invites – and I'll forgive you for calling me by a title that isn't mine anymore."

It wasn't blackmail – not quite. Who else was she going to go with anyway? One of the adolescent guys who was looking for a pretty girl to fuck and had no idea that this woman could take them out in hand-to-hand without ever reaching for a gun?

"We're going to the prom?"

"Cute, Sam. I take it that's a yes?"

"Jack..." Her shoulders slumped a little, but her expression was one of anger, not despair.

"It's just one word. A single syllable. Easy for a Doctor of Astrophysics to pronounce."

"Okay! Yes, I'll go to the prom."

"With me," he prompted, just for good measure.

She rolled her eyes. "With you."

"And you won't call me 'sir', again."

She glared. "And you won't lose your temper again if I do."

Jack grimaced. It had just been so unexpected – and like going back two years to the standoff they'd been in for years before that. "I'll try not to lose my temper if you do."

"Then I'll try not to make you lose your temper," she said, putting the inflection where he did.

Silence.

"So," he paused, theatrically. "Does this mean we're dating?"

He didn't need an interpreter to know what that look meant. Call me your 'girlfriend' and you're dead. Jack just grinned as she moved around him, pushing him out of the way.

Jack refused to be pushed. Not by this woman.

"No goodnight kiss?"

He thought she'd shove him away, offended.

Sometimes, she still surprised him.

Her hand closed about the back of his head, and the next thing he knew, he was kissing Sam.

Dear Holy God and all his angels in Heaven above... He was kissing Sam Carter!

Jack still remembered his first, first kiss. Tess McAllister had been blonde and sweet, literally the girl next-door. The kiss was brief and sugary from the donut she'd been eating. There'd been innocence and curiosity, and a lingering uncertainty about the kiss.

This was like that first kiss, and yet nothing like it.

Sam kissed with certainty. She wasn't a seven-year old, and she wasn't a seventeen year old, either. Her mouth and body knew exactly what she wanted from him, and she took it without apologies. She kissed like sunshine and youth and the smell of Krispy Kreme donuts, like laughter and desire and summer storms. As if there was nothing else she'd rather be doing and no-one else she'd rather be with.

This woman knew exactly what she wanted, and he was definitely pleased to find out it was him.

Oh, you're getting old and sentimental, Jack.

He didn't care.

He kissed her back, intending to steal her breath from her. In all of eight years, he'd never been willingly given a kiss – a real kiss – from Sam Carter.

He was kissing her now.

It might have been hours later when she pulled back. It might have been years. Jack wasn't exactly up to calculating the details.

But she looked him in the eye, a smirk written clear across her face – the satisfied expression of a woman who knew her exact effect on the man before her. He opened his mouth, and she laid a finger on it and said, "Good night, Jack."

Then she nudged him out of the way and opened the door.

Jack stuck his arm across the opening. Sam looked up at him, eyebrows raised in query. "I guess this changes things?"

She smirked. "I guess it does."

He grinned slightly and brushed his thumb across her bottom lip. "No home base tonight?" He twinkled at her in mischief and she met his gaze coolly.

"You're pushing your luck."

He shrugged, still grinning. "Hey, it's elastic. It'll hold okay."

Blue eyes rolled in exasperation and she slipped out the door with a, "Goodnight, Jack."

An hour later, his chem study finished, Jack went to bed with a smile.

Some things never change.

Some things do.

- fin -

AUTHOR'S NOTES 2: Several people have asked about their living situation. At present, I have them living in the same household, but in separate rooms. Are they boarding with a family? Living alone? Under the care and guidance of the Air Force? I'm afraid I don't know beyond the parameters of this story! Sorry.