The thing about one night stands, Derek muses as he goes over a file with Prentiss and covertly watches Spencer out of the corner of his eye, is that they really only work with strangers. Anything else and you go from fucking to fucking everything up. It's been nearly two weeks since that night and nothing's the same any more. Spencer's distant and he hasn't smiled at Derek once since he showed up at work with a stony expression he must have borrowed from Hotch and a hickey just barely peeking out from under the high collar of his shirt. Which, you know, Derek understands. He shouldn't have just left.

It was a shitty, stupid thing to do. Even with the strangest of strangers he would have written a note. Sneaking out in the middle of the night isn't like him, but he's been been doing a lot of things lately that aren't like him. Especially where it concerns Spencer. He can't even apologize for it because every time there's the slightest chance of their being alone together, Spencer comes up with some excuse to run away. His mother would probably call it karma or maybe say something cliche about turnabout being fair play. She'd be right to.

The most infuriating part, Spencer decides as he watches Derek talking to Prentiss across the bullpen, is that he wasn't lying when he said things wouldn't change. As far as he can tell, Derek isn't at all affected by the night they spent together. He hadn't expected to wake up and find Derek still in bed with him. That traitorous, squishy spot in his chest might have wanted it, even yearned for it a little, but it hadn't been a surprise to roll over and have his outstretched arm hit nothing but long cooled sheets. Spencer purses his lips together and spins his chair around so that his back is to Derek. There's no use dwelling on what's already happened.

They're adults. They work together. Things are tense, but it's his own fault. He should never have let things progress as far as they did, and he certainly shouldn't have come out of it all expecting for Derek to feel anything about it. It's just fucking. Even Spencer's capable of just fucking.

Spencer sighs and slumps back in his chair, steepling his fingers in front of his chest. Anyone looking at him would think he's lost in some important thought, but it's actually the exact opposite. The bustle and chaos of the bullpen roars on, but Spencer takes one deep breath after another and pushes everything out of his head. Maybe some day he'll lose control, but for now he still has this. He's his own desert island, isolated and unreachable, voluntarily locked in the one quiet corner of his mind. It's therapeutic and comforting and temporary. Time ticks steadily around him, but he doesn't track it, instead letting himself drift in its ebb. It isn't until a hand lands on his shoulder-firm and confident, but too small to be male-that he jerks back to himself. JJ smiles down at him, a faint line of concern between her eyebrows.

"It's quitting time, Spence. We're all going out to the bar. Want to come?" Spencer just barely manages to stop himself from glancing over at Derek, but something must flicker across his face because JJ squeezes his shoulder and perches on the edge of his desk. "It's been months since all of us have gone out together. Even geniuses need to get out and have some fun every once in a while. What do you say?"

"I would, really," Spencer says, and this time he can't quite stop his eyes from darting toward Derek. Warmth rushes to his cheeks when he sees that Derek's staring straight at him, his eyes dark and intense. For a moment he flashes back to the night at the club with Derek moving strong and hard and impassioned against him, his eyes just like that. Then he shakes himself and looks back at JJ, whose concern is even more noticeable. He clears his throat and shakes his head. "I would, but I already have plans with someone tonight."

JJ blinks, then a wide grin spreads across her face. "Oh really. Like a date? Is it anyone I know? Should we start rehearsing speeches about how she needs to treat our Spencer right?"

"You've been spending too much time with Garcia," Spencer says. There's a footstep behind him and Spencer can feel hot eyes boring into him. He bows his head and rubs at the back of his neck, but he can still feel the burn. "It's nothing like that. An old friend is coming into town and we made plans."

JJ opens her mouth to say something, but before she can Derek moves into Spencer's line of sight and cuts her off. "You could always bring your 'friend' along. I'm sure we'd all play nice."

There's something disbelieving in the line of Derek's mouth and the gleam of his eye that makes Spencer flush with annoyance, and his frown and voice are sharper than they'd normally be when he says, "Thank you, but no. We'll probably spend most of the night...catching up." JJ looks confused, but the way Derek's eyes widen momentarily is briefly gratifying before they narrow again and he smirks. Spencer purses his lips together and gathers his things with jerky, abbreviated movements, eager to be anywhere that isn't here. "I'll see you tomorrow."

His fingers curl into fists when Derek's teasing, almost sarcastic voice rings out behind him. "Don't have so much fun that you forget to sleep, pretty boy."

The crowd at The Auld Dubliner is modest at best, but it doesn't take too long before a pretty young thing takes Derek by the hand and leads him out onto the small dance floor. Derek goes gladly, more than eager for the distraction that her flirty smile promises. He needs something, anything to clear his mind, which is so full of intelligent eyes and narrow hips and elegant hands that it's practically spinning. He can't concentrate, can barely sleep, and if things don't change soon he doesn't know what he'll do. Right now the young woman swaying against his body seems like a good enough option.

Except when he looks into her wide, brown eyes, they're shallow, not at all the kind of eyes he could fall in to and drown in. When he grips her full, round hips, his fingers flex awkwardly as if they want to curl tighter than her curves will allow. And when her hand presses against his chest, it's warm, but it's small and dainty and doesn't burn the way that he craves.

A tiny part of his brain whispers that he should have worked to convince Spencer to come out tonight. If he's avoiding Derek to the point where he's willing to lie about having a friend come to visit, then it's only right that Derek tries to make more of an effort to put things right. He hates what they've turned into, but he doesn't know how to fix it. If he could just get Spencer to talk to him...

The woman rises up on her toes, her body sliding against his, and whispers in his ear about going someplace to 'talk'. Derek smiles automatically, but there's no tingle where she touches him, no thrill at the thought of laying her down on his bed and slowly unwrapping her lush body like an early Christmas present, no twinge of arousal at the thought of sinking into all that hot softness. He buys her a drink, even kisses her once to make certain, but there's just nothing. Well, that's not entirely true. When he kisses her, her lips tremble the slightest bit against his so much like the way Spencer's did that for that split second he's hard pressed to keep from bending her back over the bar and ravishing her mouth. But she doesn't taste right and, except for that tremble, she doesn't feel right. It's empty and meaningless and suddenly all Derek wants is to be near Spencer.

It's not even about the sex. Not completely at least. He just wants to be near him, able to reach out and touch him if the mood take him. He wants to hear the enthusiastic rise and fall of his voice as he rambles on about some topic Derek will never understand. He wants to watch his hands arch through the air when he expounds on a particularly exciting point. He wants to run his fingers through the short remains of his gorgeous hair and smell his unique scent that always makes Derek think of crisp fall nights and old library books. He misses Spencer more than it should be possible to miss someone he still sees almost every day.

Derek doesn't bother finishing his drink. He tosses down enough bills to cover his tab, waves a goodbye to the rest of the team, and hurries out to the parking lot. The ride to Spencer's apartment building is long enough that Derek manages to talk himself into and out of actually going to his door and knocking about a half a dozen times, but when he finally parks his bike across from the building it only takes him a moment to steel his nerves enough to swing off of his bike. The buzzers are broken, but that's fine because so is the lock on the outer door. Derek lets himself in, making a mental note to have a serious talk with Spencer about finding a safer place to live, and jogs up the stairs, taking two at a time in his haste. He might not have Spencer's memory, but he finds his door easily enough and, after pausing for moment to wipe his damp palms against his jeans, knocks. It's a good, solid knock and it only takes a few seconds before he hears fumbling from inside the apartment.

When the doorknob starts to turn, Derek closes his eyes and takes a deep breath to brace himself. Adrenaline races through his body and he suddenly feels a little sick. What if this wasn't a good idea? If it wasn't, it's too late now, he reminds himself as the door opens and words start to tumble out of his mouth. "Spencer, I think we need to-Who the hell are you?"

The man at the door is tall, about the same height as Spencer although a little broader and heftier, and pale with a friendly, scruffy face. His dark, longish hair is soaking wet, although that doesn't stop bits of it from curling damply, and several rivulets of water slide down his bare, toned chest to the towel that's loosely wrapped around his waist. If he's offended by what Derek said, it doesn't show. Instead, he leans against the door frame and gives Derek a blatant once over, his lips quirking in a small, amused smile at Derek's obvious discomfort.

"I'm Ethan." His smile is annoying, Derek decides. He tries to place the name, finally remembers Spencer mentioning him once years ago. Somehow when Spencer had talked about the kid he used to compete against in spelling bees and science fairs, this isn't what Derek pictured. Ethan's still watching him, his smile growing into a full blown grin. "And if pressed, I would guess that you're the infamous Derek Morgan. Spencer's told me so much about you that I feel like I already know you."

"What?" It's getting increasingly more difficult to keep from growling in Ethan's face, but Derek tries to bite back his frustration and confusion. "I am, but what are you-"

"You're kind of a dumb ass, you know that?" Ethan cuts him off, his words hard but his smile wide. He leans close enough that Derek can smell Spencer's shampoo and soap on him. The bastard looks like he's about to burst out in laughter and suddenly Derek wants to do more than just growl at him. "What on earth could possibly have possessed you to walk away from someone like him? Stupid, stupid mistake. Still, you're here now. Did you come to join in? Because I'd be okay with that. You're not exactly unattractive and it can be fun to mix things up a little sometimes. The more the merrier and all."

The cocky bastard winks, actually winks at him , and Derek digs his fingers into his thighs to keep from punching him square in the jaw for what he's implying. Derek starts to open his mouth, but Ethan's still talking, his dark eyes bright with a strange, amused gleam. "Of course, it's cool if you just wanted to tag in. I owe it to you for keeping my boy company when I wasn't around to."

Derek chokes on nothing and gawks at Ethan, who smiles blithely back at him. "Your boy?" Derek manages to spit out, the words heavy on his tongue. "What do you mean, 'your boy'?"

Ethan flashes a shit eating grin and chuckles. "I know Spencer doesn't talk about me often, but I'm sure he's mentioned that we go way back. We have history. We understand each other. Things went sour after I left the academy, but now that I'm moving here...Well, you know him. Can you blame me for still wanting him?"

Derek can't breathe. Ethan's smiling at him like they're fucking friends and talking so casually about wanting his Spencer-not that Spencer's his, but he's certainly more Derek's than this bastard's-that his stomach churns and he thinks he might be sick. He moves forward, wanting to push his way into the apartment, but Ethan doesn't move and Derek can't bring himself to touch him without hurting him, so they end up closer than Derek's strictly comfortable with. Ethan doesn't seem bothered. Derek gets the feeling that not much bothers him. He swallows, trying to force down the lump in his throat, and he's not entirely certain what he would have done if Spencer hadn't chosen that moment to wander up behind Ethan. His eyes are wide and his pretty, swollen lips are parted with surprise, but that isn't what Derek notices first. No, he doesn't even notice that Spencer's hair is also dripping wet and that a matching towel is slung low around his hips.

"Derek? What are you doing here," Spencer asks, but Derek barely hears him. All he can focus on is the scattering of purpling marks that mar his pale skin, especially one taunting one on his hip that peeks out at Derek from under the edge of the towel, the familiar satisfied gleam in his eyes, and the tell tale flush high on his cheeks.

He opens his mouth to say something, anything, but they're both just looking at him like he's the intruder here and he realizes that he can't think of a single thing to say that will get him what he wants right now. Somehow, he just doesn't think 'I finally figured out that, while the sex was great, I'd kind of like to hold your hand and stare dreamily into your eyes and talk about stupid couple stuff with you forever' is going to cut it.

"Nothing." He finally says, his voice thick and uncomfortable in his own ears. "It's nothing that can't wait."

Spencer moves like he wants to come over to him, but Ethan's still there between them with that damn smug smile in place, and Derek forces himself to start walking before either of them can say anything else.

Thank you for reading! Feedback is overwhelmingly appreciated.

ETA: Please don't bash Ethan just because you want Spencer to be with Derek. He's important to the plot and isn't going anywhere anytime soon, so if you have that big of a problem with him then you might want to sit this one out. I'm not asking you to love him, but please don't fill my inbox with comments about how horrible he is, because I don't see that he's done anything wrong other than cock blocking Derek, who had it coming considering the stunt he pulled.

Nothing belongs to me.