A/N: Thanks to Drakien69 and Doris for the beta. Any remaining errors are mine.

Age does not protect you from love, but love to some extent protects you from age. -- Jean Moreau

--/--

"I don't want a party," he grumbles, flipping the front page of the newspaper with a rustle.

"But this is the big one, Gil." Catherine smiles broadly, leaning over the break room table. "You only turn fifty once."

"As opposed to turning thirty-nine four times in a row, Catherine?" He looks up at her with a sly smirk and she slides backwards off the table, wearing an expression of theatrical hurt.

"Gil Grissom, I am shocked you would say such thing.: Catherine fingers her coffee cup and turns on her toes in an expression of mock indignation. Grissom raises his newspaper to cover his grin; Warrick, less inhibited, chuckles openly.

Catherine turns long enough to shoot them both a withering glare before plunking two lumps of sugar in her coffee.

That's when I meet Grissom's gaze over the top of his newspaper. I smile at him; I can only see his eyes and he blinks at me a little shyly before turning his attention back to the Las Vegas Sun. I don't think he's smiling back.

Within minutes, Nick and Greg both arrive and shift officially starts with a solemn dispatching of CSIs. Grissom pairs me with Nick; Nick gets the file and the briefing, I get... nothing.

Grissom didn't meet me after shift that morning. His office sits empty, the blinds drawn, and Judy professes she had seen him leave at the stroke of nine, nearly forty-five minutes ago. I sigh and gather my things; he doesn't always stay and wait for me. Sometimes I notice him avoiding me all day, assiduously, only to find him perched in the entry way of his townhouse, just waiting for me after work, no matter what the hour. On these days, after difficult cases or double shifts, he speaks without words. These are the bright mornings he draws all the curtains and pulls me into a possessive embrace the moment I enter, pressing hot, demanding kisses along my neck without invitation and not stopping until he can lay beside me, spent enough for uneasy sleep.

That he had left today without so much as a goodbye was unusual, though. A routine B&E and a gang-related assault were all that had occupied our shift, and neither was the sort of case that wears a CSI down, exposing a raw pulp of emotion. He had been... fine. He seemed fine all day, apart from all the hours he had so scrupulously avoided me.

I pull my car into the driveway in front of Grissom's townhouse. I enter cautiously, dropping my keys into a bowl by the door with a muted metallic clang. He isn't in his usual position on the leather sofa, though. Confused, I peer around the corner to find him hunched over his small dining room table -- or what passes as one in a bachelor's home -- focusing intently on something.

"Griss?" I call softly as I approach from behind, knowing how engrossed he can get and not wanting to startle him.

He starts at the sound of my voice anyway, and looks over his shoulder to find me just a few feet away.

A flash of color catches my eye and I circle to his side for a better look.

"They're beautiful," I almost sigh.

He looks back at his work quickly, as if he'd forgotten what he had been doing just moments before I arrived.

"They are," he replies simply, fingering a glass tube and tapping out one long, thin filament tipped with a small gold bead. "Callicore aegina," he offers after a moment before sliding the slender pin into the thorax then into a small block of foam.

I watch, intrigued, as Grissom's large fingertips part the stiff wings and gently press them open. I know he can be remarkably delicate with those hands, deceptively ungainly as they look. I watch him handle evidence with the utmost care at work everyday, but when those hands are on me they can whisper over my skin with a maddening softness unlike anything I've felt before. My breath hitches in my throat as I realize he uses the same deft, feathery touch to part the wings of the butterfly as he uses, sometimes, to part me.

"A colleague at UNLV hatched them recently and offered me a few for my collection," he says, still focused on the small butterfly in front of him. A jar, cold with condensation, holds several more specimens in addition to the three he has already mounted.

"I thought... maybe something was up when I didn't see you after work today," I venture after he lets a silent lull pass between us.

"Nothing's up," he replies nonchalantly.

"Oh?" I reply, knowing my brow is furrowing as I say it.

Another lapse of silence, then realization dawns.

"This is about your birthday, isn't it?"

"'This' isn't about anything. This is just a hobby." He intends to sound less defensive than he does, I can tell.

"Funny, because 'this' looks like sulking."

He looks up at me, slightly annoyed, and is met with a faint quirk of my lips, a little lopsided smile at his expense but for his benefit.

I pull out the chair next to him and sit down, ignoring the look of mild irritation before he turns his attention back to his mounting. With my elbow on the table, I prop my head up and watch him.

"You know Grissom, I must say I'm surprised."

"Oh? And why's that?"

"I never pegged you for a guy who'd make a big deal out of turning one year older."

"I'm not making a big deal out of anything, Sara," he responds in his best no-nonsense boss voice.

"Well that's good, because if you have one of those 'hundred things to do before my fiftieth birthday' lists you should know now I'm not going sky diving or having a threesome with you in the next twenty-four hours."

"What makes you think I haven't already crossed both of those off my list?"

He steals a sly glance at me and I bite my lip to keep from laughing out loud. I choose to interpret it in the manner delivered, a joke, even though he could have easily done either many years ago. Even after months of intimacy, what Grissom chooses to reveal and what he chooses to conceal seems almost arbitrary, and trying to draw any concrete conclusions about the Grissom who existed long before he knew me is often a futile venture.

I let the quip settle for a moment before speaking up again. "Well if that's the case, then what's the big deal about turning fifty? Sounds like you've met all your major life goals."

The slight smile on Grissom's face evaporated as quickly as it had materialized. "Sara, it's not about goals or milestones or... sky diving. You wouldn't understand."

"I might understand if you tried to explain it," I reply, deliberately near-whisper to keep from sounding snappish.

Grissom sighs and pins a thin strip of paper over each of the wings of his butterfly. He gropes for words, almost physically, his hands fussing needlessly with the pins and papers and ephemera spread out on the table. "Sara, it's... a question of biology. I'm not young anymore, I can't deny that."

"Do you feel old?"

"No," comes the quick reply. "I don't feel old, but the feeling and the reality..." Grissom trails off but keeps his hands busy screwing the lid back on his jar of butterflies. "You'll reach an age when you realize your own mortality, too," he says, a little suddenly.

I blink back at him and choke back my first response, the honest response that I've been all too aware of my mortality since I was twelve and I watched my father's fade in the middle of so much blood.

"You think I don't understand that?" I finally find the voice to say.

And for the first time this morning Grissom meets my gaze.

"In our line of work?" I continue, my voice still low, too low, "I'm aware of it everyday; I don't need to turn fifty to realize that what we have is fleeting and precious." I pause, raising my free hand to stroke his beard. "If I didn't I wouldn't have stuck around waiting for so long. I would have settled for something less. Something less than perfect."

Grissom leans into my hand and with my thumb I trace small circles on the smooth skin just above his beard. I give him a moment, but he just sighs and lets his eyelids slide shut, lost in my rhythmic ministrations.

With his eyes closed like that, with just the faintest play of a smile on his lips, he looks so young. The slight creases in his forehead melt away, and I can imagine what he looked like as a very young man, younger even than when I first met him, thirty-something and vibrant and maybe just a little bit reckless.

"Grissom, you're not old," I say a little suddenly, surprising even myself a bit, but I mean it.

He opens his eyes and regards me for a minute.

"I don't--" He clears his throat and looks away. I can't help but silently plead for him to look back at me. "I don't feel old when I'm around you. I feel... like I'm catching up on everything I ever missed. All those years without you, before I knew you, before I'd let myself know you..."

"You can't get them back, but you don't need them back. You've got right now."

Apparently this is the right thing to say because his eyes meet mine again and he manages a smile.

"Maybe it's just because I still can't believe you're here. Or rather, I still can't believe you stayed," he adds with a little bit of the joy back in his voice.

"You think after everything you've done to push me away seeing you first thing in the morning would be what finally succeeded? Give me a little credit, Gil."

Then his hand is on my wrist, pulling it toward his lips. I know he's smirking now, I can see his cheeks rise behind my hand and the skin around his eyes crinkles. He plants a kiss on the back of my hand then lets it wander lazily up my arm, an ambling trail of kisses that ends at my elbow, with Gil and me leaning halfway out of our chairs to meet awkwardly in the middle.

I scoot my chair forward a little ungracefully and he uses the relaxed space to finish his march up my arm, marking the trailhead in the crook of my neck, just below my ear. I giggle a little -- it's a loud, unfamiliar noise -- but the tickle of his beard across the sensitive skin of my neck is too intense. Pleased with himself, he does it again, and I squirm involuntarily away from him and out of my chair, tripping backward onto the carpet with a shrill cry of surprise.

Grissom stands and offers me his hand, straight-faced, and I grumble as I take it. He lifts me easily onto my feet -- he's stronger than I remember. He takes the opportunity to pull me straight into his arms and I relent, folding my arms around his back. He smells good; he always does, and radiates a soothing heat that I could just melt into for hours--

"So do I have a cake?"

"Huh?" I'm a little groggy and his voice cuts through my quiet enjoyment of the moment.

"For my birthday -- did you get me a cake?"

I lift my head from his shoulder to find him looking at me, smiling hopefully.

"Your birthday's not until tomorrow." I try my best to sound authoritative.

It's comical, I guess, because he keeps on smiling and nudges my chin with his nose. "You didn't plan ahead?" he asks innocently.

"You're incorrigible," I sigh, titling my chin enough to give him easy access to my clavicle.

He avails himself of the opportunity and kisses me there, too. "Mm, Sara?"

"Yeah?"

"When I was a little kid, my mom would let me open one present the night before my birthday."

"...And?"

"And I'm not one to break with tradition," he breathes into my shoulder. "So?"

"So?" I repeat back, teasingly.

"So what do I get tonight? As a birthday-eve gift?"

"This is your first birthday with me -- that's not good enough for you?"

He stops for a moment, as if to ponder this. "Mm, second-best birthday present. Definitely," he mumbles.

"Second best?" I place both my hands on his shoulders, pushing him a few inches away from my chest.

He meets my questioning look with a quirk of his own eyebrow and a slight shrug. "I got a chemistry set when I turned eight."

"A chemistry set? That's better than... this?"

"It was a really nice chemistry set."

And so I kiss him, deeply this time, lips to lips that becomes tongue to tongue, teasing a moan from somewhere deep inside Gil's chest. And I keep kissing him, reveling in the hot slide of my lips over his and the way his breath flutters across my cheek and his hands grasp at my back, pressing me as close as physically possible.

He nips my lower lip and is rewarded with his own low, hungry noise as my hands twine through his hair. We may be doing this for the thousandth time -- I lost count months ago -- but every time I lose myself in it, utterly, and never want to let him go.

Grissom breaks the kiss, pulling back enough to watch my face as he licks his lips. "Okay," he breathes, "better than the chemistry set."

I laugh and smooth the hair down on his forehead.

"In fact, it's so much better that I might have to turn fifty again next year," he adds, his lips whispering over mine.

"Even better -- you can turn fifty again tomorrow."

Then he's kissing me again, covering my smile and teasing it away with the hot press of his mouth. And it's perfect, because it always is, and because the warmth of his body against mine and the steady beat of his heart under my fingertips is the only reminder that we may not have forever, but we always have today.