A/N: Artemis isn't mine.

On becoming an axiom

That flicker in his eye, the one just after you say, "I love you," is gone.

It's not there before he says, "I love you," in return.

It's not there when he kisses you, his lashes dipping as yours fall to nestle comfortably against your cheeks. His blue eyes no longer stay wide open, boring curiously into your face long after yours are closed.

He never stops thinking. It's always lurking there, behind his eyes: the hesitation, the consideration, the flicker of thought.

But now, it's never of you. Even as your bodies twine together in the night, his thoughts are of gold, or theft, or quantum physics, or blackmail – never just you.

He falls asleep beside you in absolute trust, skin moon-pale in the darkness, brow furrowed in deep thought even in his dreams. When he wakes, he kisses you distractedly before hurrying off to set whatever plan he's come up with during the night into motion.

He never thinks about you, anymore – but far being upset, you find it empowering.

The flicker is gone.

He finally knows what your love – what his love – means. You are understood, categorised, and filed away in a corner of that brilliant mind.

You're not a statistical anomaly, a blip in his otherwise consistent results. You're not a puzzle.

You're a given, a fundamental, a known quantity with a reason for existence and no reason ever to cease to exist. An axiom, without which his life would make an entirely different and lesser kind of sense.

He doesn't need to think about you, anymore.

He understands your love and is no longer intrigued by it, because he no longer needs to constantly plan for when it will change or be taken away. This is acceptance, this is trust, this is intimacy, this is love – it is – or as close as he can come to it.

You pause at the door of his study, leaning against the doorframe and gazing in at his dark head bent over a sheet of figures. A gentle smile tugs at your lips as he spins away to resume typing on his computer at something close to the speed of sound. Funny, how even his work habits can be so endearing, just because they're so him.

"I love you, Artemis," you call to him, and you mean it, but he doesn't pause in his work.

"I love you, too," he says.

It's automatic, not disrupting his train of thought or the movement of his fingers on the keyboard in the slightest. He may not even have consciously noticed you were there; now, you fade into the background for him as easily as Butler. But he means it too.

You push away from the doorframe, contentment as sharp as pain in your chest. The flicker is gone. And you don't miss it in the slightest.

A/N: I have lots of authors notes to go with this one, because this is possibly my most personal, most soul-baring piece ever, but I've decided not to put them in. I'm not sure whether it came across how I meant it at all, because I've never written anything quite like this before. It's sort of a more explicit extension of what I tried to do with Timmy and Angeline in HSF, and it obviously didn't come across properly there. So please be free with concrit!