Stiles was sitting in Starbucks playing Flappy Bird when Lydia came rushing in, hair out of place and a crazed glint in her eyes.
"Who did you kill?"
"What?" Lydia scowled, pinning back stray strands of hair. "Shut up Stiles. I have good news!"
Stiles waited for a few seconds before realising she hadn't continued. He looked up to find her stony glare waiting on him. "Oh! Right! Good news? What is it? I am so invested in this conversation right now, and not beating my running streak on- hey!"
The redhead smirked, tucking his phone into her purse. "You know that research I prepositioned? I'm a finalist for the grant!"
"Seriously? That's amazing Lyds!" he grinned, halting mid-rise when she rose her hand in a stopping motion.
"That's not all. It's for 25 thousand bucks, there'll be an article written about me and my research, AND it's administered by Derek fucking Hale." she grinned manically at the name. "I will get to see the mysterious Hale in three-dimensional, high definition reality."
"Wait," Stiles halted. "Derek Hale? As in my ex-Derek?"
Lydia's face managed to morph through ten emotions at once in that moment, settling on astonishment. "Greek-God Derek? Why-the-hell-would-you-end-it Derek? Moping-for-four-months Derek? That Derek is Derek Hale, the award-winning mathematician and general science God?"
Stiles nodded exuberantly. "We actually ended on pretty good terms, once I got over the moping. I could put in a good word for you, like drop a text or something!"
"You dated a mathematician?" Lydia muttered to herself. "Wait, what? 'Drop a text'? Hell no Stilinski. If you're going to put in a good word for me, you're going to put in a good word for me, not a freaking text. Strike up a conversation, and somewhere along the way drop the whole 'hey, you're administering a grant thing', and then arrange dinner for the three of us. Or four. Is he single?"
Stiles gulped a little at the idea, but knew that Lydia would murder him if he didn't at least try. A grant could make her leap from run-of-the-mill genius to mathematics extraordinaire.
"Sure. I'll try to put something to- try, Lydia! I'll try!"
It wasn't until she was halfway down the block, already tapping away on her phone, that Stiles realised she still had his phone. And he'd totally been on the start of a winning streak too.
"I cannot believe that I am about to meet Derek Hale. THE Derek Hale. Like, sure, I saw him once or twice when you two were hooking-up, but only seeing, and if I had known...Derek Hale."
"Yeah, yeah, think you can let go of my hand before it breaks?" Stiles muttered, retracting his hand from her manic grip. The restaurant was nice, one he and Scott went to when they first arrived in the city. A celebratory this-is-the-last-nice-thing-we-can-afford meal. Now Stiles was 26 and a professional psychologist, hoping to become a professor in the next few years. Scott was living in Oakland with heavily twin-laden fiance Kira. Lydia was engaged to Jackson, their wedding on hold until he finished his work in England and ended the three-year span of long-distance their relationship had taken. And Derek was...
"Here. He's here. Ohmygod. Play it cool Stilinski. If you mess this up with your spasticness, I will set Jackson on you."
Stiles was only half-listening. Derek somehow managed to look even better than he did two years ago, when they last saw each other face-to-face. He was wearing framed glasses with his black suit, hair gelled into a perfect quiff. And when he caught Stiles' eye, that grin lit up his face, flaunting those perfect bunny teeth.
"Stiles," he grinned, enveloping him in a hug as soon as he'd rose.
"Derek. You're looking great!" His voice was slightly muffled by Derek's suit, which his face had ended up pressed to.
"Yes, yes, we're all looking fabulous. And while I love heartfelt reunions, our standing is catching attention," Lydia said from somewhere behind him, smirk evident in her tone. For a second Stiles thought Derek stiffened at her voice, but then he was removed from the hug and hustled back into his seat across from him.
"Sorry. Derek Hale, Lydia Martin. You're both super-nerds. Converge."
Lydia sent him a half-hearted glare at that, while Derek breathed out a laugh. Slightly ironic as his smile still left Stiles totally breathless.
"Well, it's an honour to meet you. I've followed your work since you were first published, and your work has basically pushed my theories into existence!"
"That's nice," Derek smiled. "I'd like to say the same but I usually only follow competing mathematicians, and I don't recall Stiles mentioning you during our time together."
Stiles' head looked up at his name. "Well, no. Lydia had only just moved back from New York at that point, and we'd barely gotten any time to reconcile."
They smiled at each other at that point, Stiles mentally pushing away Lydia's doubts. She was awesome. Derek would be a dumbnut to not pick her.
"It's a nice place," Derek cut in. There was a small furrow in his head as he thought, breaking into a grin. "Is this the same place that...do you remember? That time in January..."
"Oh my God!" Stiles clapped his hands to his face, ducking down slightly. "I completely forgot!" The pair broke into muffled sniggers, trying to avoid attention. Lydia smiled uncomfortably, her spidey senses tingling with suspicion.
"Apparently neither do they, or I'm pretty sure we'd never be allowed back in," Derek smirked, breaking another bout of laughter from Stiles.
"Jesus. Look, I'm gonna go to the toilets so you guys can get your nerd on. Don't break anything."
He said the last part with a barely concealed smirk at Derek, who's face split into a grin as he watched him leave.
"You guys were close?" Lydia started with, drinking her water innocently. She didn't miss the way Derek's eyes fell when she spoke up, like he'd been pretending she wasn't here at all.
"Yeah, we were. So, your research proposal?" Derek questioned, changing the topic immediately. His smile was colder towards her, barely civil.
"Well, it's based back in South America. There have been a good seven research trips that either failed or weren't completed, and there's so much data from that vicinity that could be collected. I only need about-"
"Break-up with Stiles."
Lydia choked slightly on her own spit. "Excu...what?"
"What?" Derek replied innocently.
"Did you just say...break-up with Stiles?"
"Maybe? It's just...I haven't seem in so long, and we ended with so much unsaid, and everything's just rushing back! I'd forgotten just how...Stiles he is, and I'm going to need you to break up with him."
"Derek," Lydia began. She was in so much shock she didn't even have a grin to fight, because damn it, she KNEW they had unfinished business to fuck out. Or talk out, since neither seemed like the one-night kind of guy. "Derek, I'm engaged," she said pointedly, showing him the ring on her left hand she'd been wearing for four years now. At that Derek's face fell, a little bit of embarrassment tinging his ears red.
"God, I am so sorry, I didn't think you two were...please just forget I said anything?"
"Wait, that isn't what I-"
"How's it going my baby Einsteins?" Stiles grinned, sitting back into his seat. Derek grinned back, only to duck his head in an attempt to conceal it. Lydia refrained herself from banging her head against the table. "We might want to escape sharpish, because I just met the cook in the bathroom and it turns out he definitely does remember us."
That time Lydia didn't bother to refrain herself.
"Your ex is insane."
Stiles fell gracefully from the couch at Lydia's announcement. "What the hell Lydia? I give you a key for emergencies. And Derek's in perfect mental health. I should know, I'm a psychologist."
"Psychologist, not a psychiatrist. There's a difference. And I need you to fix this before the meeting tomorrow, because right now he hates me."
"He doesn't hate you! Didn't you see him at dinner? He was civil. He smiled. It took me weeks just to stop him from glaring."
Lydia rolled her eyes, collapsing on the couch next to Stiles' feet. "Do you want to know what Stiles? He does hate me. He hates me because he thinks we're engaged, and he's still in love with you!"
"What?" Lydia grabbed his leg to stop him from collapsing to the floor a second time. "Derek isn't in love with me! He was the one who ended it, with his work and our differences and shit. And since when were we engaged? I'm not against the you part, just the part where Jackson punches me in the face."
"We're engaged because he's a stupid idiot, and if you're seriously not going to believe me, we're going to talk to him. Right now." She yanked him to his feet, marching him out of the apartment with just enough time to grab his keys and shoes.
"What? We're just going to hang around his building like a pair of creepers, jumping on him when he emerges to ask him whether or not he's in love with me? Great plan Lyds. No wonder you're up for a grant," Stiles drawled sarcastically.
"Don't be an idiot. I hacked into the account and got his office number. Now stop falling over and hurry up! The day is fading, and romance awaits!"
Stiles huffed after her, wondering when he suddenly became friends with a maleficent master of Disney-proportions.
The building was fancy, an old college or something. Derek's door was varnished wood, Professor engraved on a sophisticated golden plate. Somewhere along the way, Stiles had completely forgotten the reasoning to why he was here, mainly because there was none. Lydia stood with that manic glint back in her eyes, hand tapping the door three times.
"Come on in," Derek called out from inside the room. Lydia pushed open the door, sighing and pushing Stiles in before her.
"Stiles! And Lydia," his voice dropped a little. "What are you two doing here?"
Lydia marched forward to the middle of the room, standing with arms crossed. "You're in love with Stiles."
Stiles was still standing where Lydia pushed him to, watching as Derek's face reddened and his eyes widened with shock. "What? I'm not...you two are..."
"Us two are friends. I am engaged to my highschool sweetheart, who's moving back from London in a few months. Stiles is single, and has probably never gotten over you. Now please, for the love of life, TALK!"
The two stared at each other, the only sound Lydia's slightly heavy breaths.
"You're single," Derek whispered.
"You're in love with me," Stiles replied, crossing his arms defensively.
"I miss you. A lot." He stepped closer.
"You broke up with me. And it hurt. A lot." He stood his ground.
"I shouldn't have done that. Biggest mistake of my life." He looked so fucking nervous.
"Damn straight. I probably shouldn't even take you back." Two years had done nothing to his attitude.
"But...?" He reached out and tugged at one of Stiles' hands, grinning slightly when he gave and released from his defensive hold.
"But since when did I do what was better for me?"
Derek leant down, pushing their lips together with matching smiles on their faces. Lydia sighed with relief.
"Thank-freaking-God. Use protection!" she called after her, slamming the door shut and grinning ferally at a passing grad student who eyed the door with slight disappointment.
Maybe the meeting would go okay tomorrow after all.
It was seven months later, at Lydia and Jackson's wedding, that Lydia and Derek met again. She had gotten the grant, and managed to get Jackson in on the trip, so they spent that time proving theories and planning their wedding from four hours ahead. When Allison, her maid of honour and co-wedding planner, had sent her the RSVPs, and she'd seen the neat tick next to 1+ and too-neat handwriting on Stiles' card, she'd screamed loud enough for Jackson to get the shotgun. Something both of them would deny for the sake of their reputations.
Derek was awkwardly standing to the side while Stiles and Scott danced to a cheesy pop song the band were playing when she attacked.
"Derek."
He jumped, and tried a manly cough to cover it up. "Lydia. You look amazing!"
"I know," she smirked. "Not so bad yourself. Look better as a pair though."
His face was caught in the headlights, mouth open as he tried to figure out a reply.
"Also a lot more eloquent on paper, apparently. I hope you'll be reading my results when they get published next months, now that I'm a 'competing mathematician'." She grinned once more, leaning in to kiss him on the cheek as the song ended. "Take care of our Stiles. Hurt him, and we'll get you back tenfold."
"I don't doubt," he muttered as she sashayed away, remembering his first meeting with new mum Kira. She'd excitedly shown him her weapon collection when Stiles mentioned he took combat, and almost cut his toe off when she dropped her katana in an exuberant speech about knife safety. The irony was almost painful.
There was a tug on his hand, and he turned to meet Stiles. "Heya! Scott's dancing with Kira. Wanna join me on the floor?"
"Sure," Derek grinned, kissing him lazily. "But I'm going to be taking this," he turned Stiles around, trapping him in his arms as he downed his half-finished glass of champagne, "as we are avoiding all repeats of Scott's bachelor party."
Stiles sniggered at the memory, hand finding Derek's to pull him forward. Their fingers brushed against the matching rings they wore on different fingers, a reminder that tonight was Lydia's. "I hope you're just referring to the stuff that happened in the bar, because I am certainly looking for a repeat towards the rest of the night."
He grinned ferally, eyes lighting up as Derek knocked his head back with laughter, the pair lazily twirling in and out of other couples. Lydia smiled from across the room, her husband's arm around her waist and that bloom of accomplishment in her stomach, reputation be damned.
Human AU set in San Francisco. I have no first hand knowledge of San Francisco (or America in general), nor mathematics (I am only GCSE level at mo). Idea taken from a few Friend-based one-shots I've seen around, like this piece of awesome- post/107261282987/hey-your-writing-is-amazing-and-i-really-like
Characters belong to Jeff Davis, and plot/some of the lines have been taken from Friends, episode 'The One with Ross' Grant', written by Sebastian Jones.