Theodore Nott x Bestfriend Reader
Before they could even walk, their mothers had already decided they’d be inseparable.
Christina Nott and Cressida Selwyn had met at Hogwarts — both proud Slytherins, both sharp, elegant, and utterly loyal to one another. They’d survived school, marriages, and the complicated politics of pure-blood society side by side. So when their children were born within three weeks of each other, the friendship naturally became a family tradition.
Theodore Nott and Y/N Selwyn — the heirs to two of the oldest, most respected Slytherin families — had shared playpens, tutors, and tantrums. If one was missing, the other was guaranteed to be nearby.
As children, they’d crawl under the dining tables at the Notts’ estate, whispering plans of running away to become famous Quidditch players. They’d steal pastries from the Selwyn kitchens and get scolded by house-elves who secretly adored them. Their mothers would just exchange knowing smiles, already resigned to the fact that the two of them were a package deal.
When Hogwarts letters arrived, they opened them together — both stamped with the same green wax seal.
From the moment they stepped into the Great Hall and the Sorting Hat barely touched their heads before shouting “Slytherin!”, everyone knew it was fate.
For years, they were just Theo and Y/N.
Late nights studying in the common room.
Partners in Potions, always arguing but never apart.
Firewhisky-fueled laughter after curfew, sneaking down to the lake with Mattheo, Draco, and the rest of the boys.
Everyone saw it — the quiet glances, the unspoken loyalty, the way Theo’s eyes softened only for her. But when anyone dared to tease them, both would immediately scoff.
“He’s like my brother,” Y/N would say, rolling her eyes.
“She’s basically family,” Theo would insist, his voice a little too quick.
And so it stayed that way — for sixteen years.
By sixth year, Theodore Nott and Y/N Selwyn were a Hogwarts constant.
If Theo was in the library, Y/N was beside him — sprawled across the desk, humming to herself while he studied.
If Y/N got caught sneaking back to the common room past curfew, Theo was the one making up the excuse that got her out of trouble.
And if either of them was seen without the other, someone, somewhere, would inevitably ask, “Are you two finally dating yet?”
“Merlin’s sake,” Y/N muttered one morning in the Great Hall, stabbing her fork into a piece of toast. “If one more person asks if we’re together, I’m hexing them.”
Across from her, Theo smirked over the rim of his coffee cup. “You hex people for fun, Selwyn. That’s hardly a threat.”
Mattheo Riddle, sitting beside him, grinned. “Maybe people wouldn’t ask if you didn’t act like a married couple.”
Y/N shot him a glare, her expression deadly but her tone playful. “We don’t act like a married couple.”
Draco leaned forward, amused. “You do realise you literally argued over what colour tie he should wear this morning?”
Theo gave an unbothered shrug. “It clashed with her hair. She was right.”
Mattheo dropped his fork with a laugh. “Oh, you’re gone, Nott.”
Theo’s ears flushed faintly pink, but he didn’t rise to the bait. He’d learned long ago that fighting back only encouraged them. Instead, he turned to Y/N, pretending not to notice the way her eyes caught the sunlight or the faint green shimmer on her nails that matched her tie.
She’d always been beautiful — but lately, it was different. She carried herself differently. The confidence, the teasing smirk, the way she seemed to draw every eye in a room without even trying.
It wasn’t that he hadn’t noticed before. He just… hadn’t let himself.
Now, every time someone looked at her a little too long, every time she laughed at someone else’s joke, something uneasy twisted in his stomach.
“Alright,” Y/N said, rising from the table, her bag slung over her shoulder. “Potions next. Try not to get distracted, Theo.”
“I don’t get distracted,” he muttered automatically, following her out.
Mattheo called after them, “You do when it’s her!”
Y/N only tossed her hair and looked over her shoulder, grinning. “Jealousy doesn’t suit you, Riddle.”
Theo tried not to smile — he really did. But Merlin, she made it impossible.
The Slytherin common room was buzzing that night — green flames dancing in the fireplace, soft laughter echoing off the stone walls. Someone had smuggled in bottles of Firewhisky, and the faint scent of smoke hung in the air.
Theo sat slouched in one of the leather chairs, pretending to read a book while his friends lounged around. He’d been on the same page for ten minutes.
Across the room, Y/N sat cross-legged on the rug, wand lazily levitating a deck of Exploding Snap cards while Enzo and Pansy argued over the rules. Her laughter — soft, familiar — cut through the noise.
“Not studying tonight?” Mattheo asked, sprawling onto the couch beside Theo.
Theo hummed in response, eyes still following Y/N. “I’m reading.”
Mattheo snorted. “Right. And I’m Head Boy.”
When the cards exploded in a puff of smoke, Y/N threw her head back laughing, eyes crinkling at the corners. Theo’s mouth twitched despite himself.
Mattheo noticed. “You know, if you’re going to look at her like that, at least do something about it.”
Theo’s eyes flicked up, sharp. “She’s my best friend.”
“That’s adorable,” Mattheo said dryly. “Now tell me the one where you don’t stare at her like you’re planning your wedding vows.”
Theo exhaled through his nose, shutting his book. “You’re drunk.”
“Not yet.” Mattheo smirked, leaning back. “But you might make me if I have to keep watching this tragic slow burn.”
Before Theo could respond, Y/N appeared, plopping herself down onto the arm of his chair — close enough for her perfume to make his brain stop working properly.
“Riddle’s trying to convince Pansy he can outdrink her,” she said with an amused grin. “Should I start taking bets?”
Theo tilted his head toward her. “I’d put ten Galleons on Pansy. He’ll be unconscious in an hour.”
Mattheo raised his glass from the couch. “I heard that, Nott!”
Y/N laughed, and the sound went straight through him.
She nudged him with her knee. “You’ve been quiet tonight. Everything alright?”
Theo forced a small smile. “Just tired.”
But she saw through it — she always did. Her gaze softened for a second, lingering on his. “Don’t overthink everything for once, yeah?”
He wanted to say I’m trying not to, especially when you sit this close.
Instead, he gave a low chuckle. “Noted, Selwyn.”
“Good.” She grinned, hopping up again. “Because you’re coming to Pansy’s party tomorrow. No excuses.”
She pointed her wand at him in mock warning. “I mean it, Nott. You’re going. You never come to these things anymore.”
He sighed, leaning back. “I don’t like parties.”
She smirked, already walking away. “You’ll like this one.”
Mattheo laughed into his drink. “Oh, you’re doomed.”
Theo didn’t answer — just watched her disappear up the girls’ staircase, feeling that same uneasy twist in his chest.
He had no idea how right Mattheo was.
“Hold still, or I’ll hex you,” Pansy said, wand in hand as she finished fixing the shimmer along Y/N’s collarbone. “You look criminally good, by the way.”
Y/N rolled her eyes but smiled. “It’s just a party, Pans.”
Pansy arched an eyebrow. “A party that Theo Nott is finally attending after two years of hiding in the library. You’re welcome, by the way.”
“I didn’t make him come—”
“Oh, please,” Pansy interrupted, grinning. “If I told him it was anyone else’s party, he’d still be in the dungeons pretending to read. You’re the reason he’s showing up, Selwyn. Don’t insult my intelligence.”
Y/N gave her a look but didn’t answer. Deep down, part of her knew it was true. Theo rarely bothered with parties, but when she asked — no, demanded — he’d sighed and agreed. That was the thing about him. For all his quiet, stubborn moods, he never could tell her no.
Pansy stepped back to admire her handiwork. “There. Perfect. If he doesn’t combust when he sees you, I’ll be shocked.”
Y/N turned toward the mirror. The emerald silk dress shimmered under the candlelight — simple but fitted, elegant with just enough edge. Her hair was soft and loose, the faintest trace of silver around her eyes. She looked older. Sharper. The same, but not.
“Merlin,” she muttered, tugging slightly at the neckline. “It’s too much.”
Pansy smirked. “Exactly enough.”
Down in the common room, Theo was already there — leaning against the wall with a half-empty glass of Firewhisky, watching the growing crowd.
He wasn’t sure why he’d let Y/N talk him into this. Maybe it was the way she’d looked at him when she’d said “You’re coming.” Maybe it was the idea of her surrounded by people like Barty Crouch Jr. — the kind of blokes who didn’t know when to stop flirting.
The thought made his jaw tighten.
Mattheo clapped him on the shoulder. “Cheer up, mate. You look like you’re about to attend a funeral.”
Theo shot him a glare. “I’m fine.”
“Right,” Mattheo drawled. “So fine that you’ve checked the stairs twelve times in the last five minutes.”
Theo opened his mouth to retort — and then she appeared.
Y/N descended the stairs with that effortless grace she always had, laughing at something Pansy whispered beside her. The green of her dress caught the light, matching her eyes almost perfectly.
For a moment, the noise in the common room dulled. Theo didn’t even realise he’d stopped breathing until Mattheo elbowed him lightly.
“Careful, Nott,” he murmured. “You’re staring.”
Theo forced his eyes away, jaw tight. “Shut up.”
Y/N spotted them and smiled — that smile that had been undoing him since they were kids.
“You came,” she said when she reached him, slightly out of breath from the stairs.
“You also said that last time, then disappeared halfway through.”
He gave a small, reluctant smirk. “Guess you’ll have to make sure I stay.”
Her grin widened, playful and dangerous. “I think I can manage that.”
The music pulsed through the room, low and heavy — a thrum that seemed to match the beat of Theo’s heart. The air was thick with Firewhisky and laughter, flickering green light spilling over velvet and glass.
In that emerald dress that looked like it had been made to taunt him.
She was dancing — spinning beneath the lanterns, eyes bright, smile easy. The hem of her dress brushed her thighs as she moved, the sound of her laugh slicing clean through the noise.
Theo had seen her laugh a thousand times before. But this one — this one wasn’t for him.
Because standing beside her, close enough to touch, was Barty Crouch Jr.
Theo’s jaw flexed. His fingers tightened around the glass in his hand until it cracked faintly. He could barely hear Mattheo over the blood rushing in his ears.
Barty leaned down, said something against her ear.
She laughed — low, warm, the kind of laugh Theo used to think was his.
And then Barty’s hand slid around her waist.
Theo went still. Every muscle in his body locked.
Across the room, the light caught on her hair, her smile — and the smug way Barty looked at her like she was a game he’d already won.
The room blurred around him. The music dulled.
All he could see was her.
Mattheo’s voice cut faintly through the haze. “Oh, bloody hell. There it is — the Nott explosion countdown.”
Theo didn’t answer. He set his drink down hard enough for the liquid to slosh over the rim.
He didn’t think — didn’t care.
Through the crowd, through the pulsing light, every step like a fuse burning shorter. His eyes never left her.
Barty turned first, that smug grin twisting just slightly when he realised who was coming.
He reached them, hand closing around Y/N’s wrist — firm, possessive, not enough to hurt but enough to make her breath hitch. She turned, confusion flickering across her face just as he pulled her toward him.
The world spun — music, whispers, green light — and then his mouth was on hers.
It wasn’t soft. It wasn’t careful.
It was six years of restraint snapping all at once — desperate, reckless, and everything he’d been pretending not to feel.
Mattheo’s low whistle cut through the air. “Finally.”
For a heartbeat, the world stopped.
The music stuttered out, whispers rising around them like a wave. Theo could hear his own pulse pounding in his ears — fast, wild, uncontrollable.
Her lips were soft, warm, unmoving for half a second before she pulled back with a small gasp. Her hand came up instinctively to his chest, stopping him.
“Theo—” her voice was barely a whisper, her eyes wide, startled, searching his.
He didn’t say anything. Couldn’t. His breath was ragged, his mind white noise.
Around them, the crowd had gone quiet — everyone frozen, half in shock, half in delight. Pansy’s mouth hung open. Draco looked like Christmas had come early. Mattheo was smirking into his drink, clearly fighting the urge to cheer.
And then there was Barty.
He stood just a step away, expression hardening. “What the hell was that, Nott?”
Theo finally tore his gaze from Y/N long enough to look at him — a glare so sharp it could’ve cut glass. “Don’t touch her again.”
Y/N blinked, still catching her breath. “Theo, stop—”
But he didn’t. His voice was low, dangerous. “You think you can talk your way into every girl in this castle, Crouch? Not this one.”
Barty scoffed, taking a step closer. “Didn’t realise you’d claimed her.”
The words hit like a slap — not for Theo, but for her.
She turned sharply toward Theo, eyes narrowing, fire flickering beneath the shock. “Claimed?”
Theo’s expression faltered, realisation flashing through the haze of adrenaline. “That’s not what I—”
“Then what was that?” she demanded, voice low but shaking with emotion. “Because from where I’m standing, it looks like you just decided for both of us.”
He opened his mouth, but no words came.
For the first time in his life, Theodore Nott didn’t have a single thing to say.
Y/N stared at him a moment longer, chest rising and falling fast — the weight of six years of friendship pressing between them.
Then she shook her head, turning away. “You can’t just kiss me because you’re jealous, Theo.”
And she was gone — pushing past him, past the crowd, disappearing up the stairs as whispers erupted behind her.
Theo stood frozen in the middle of the common room, the taste of her still on his lips, the silence louder than any noise.
Mattheo sighed from the couch, swirling his drink. “Well,” he muttered. “That went well.”
Theo didn’t answer. He just stared at the empty staircase, jaw tight, chest aching with something he couldn’t begin to name.
The corridors outside the common room were quiet, the air cool against her flushed skin. Y/N barely realised she was walking until she reached the end of the hall and leaned against the stone wall, heart pounding like she’d just run a race.
Her fingers brushed her lips.
For years, people had teased, joked, assumed — and she’d always laughed it off. Because it wasn’t like that. It couldn’t be. Theo was… safe. Steady. The one constant in her life she didn’t have to question.
Now she couldn’t stop replaying the look in his eyes before he kissed her — the anger, the jealousy, the need.
That wasn’t the Theo she knew.
That was someone who’d been holding something back for a long, long time.
“Bloody hell,” she muttered, pressing her palms to her face.
She didn’t even know what she felt — anger? shock? something she couldn’t quite name but burned anyway.
He had no right. No right to just decide that moment for her.
When he kissed her, something inside her had sparked — a flash of heat, recognition, memory. Like part of her had always been waiting for it, even if she’d never dared to admit it.
The worst part was that it hadn’t felt wrong.
Behind her, the sound of footsteps echoed faintly down the corridor. She didn’t turn — she didn’t have to. She already knew that walk anywhere.
“Theo, don’t,” she said quietly, not looking at him.
He stopped a few feet away, his voice rough. “Y/N—”
“I don’t want to hear it.” She turned then, eyes sharp despite the wobble in her voice. “You can’t just— Merlin, you can’t do that.”
He looked wrecked — hair disheveled, shirt untucked, the usual calm gone from his face. “I know. I shouldn’t have—”
He hesitated. “Because watching him touch you felt like someone was twisting a knife in my chest.”
The words hit hard enough to make her breath catch.
He ran a hand through his hair, frustrated. “I didn’t plan it, I just— I’ve spent my whole life trying not to feel this way, and tonight I— I couldn’t stop.”
Y/N stared at him, her heart betraying her with every fast, uneven beat.
He stepped closer, slow, careful. “Tell me you didn’t feel anything when I kissed you,” he said quietly. “And I’ll walk away. I swear.”
Her throat went dry. She wanted to say it — wanted to tell him he was wrong, that it hadn’t meant anything.
But the lie stuck in her mouth.
Theo’s eyes searched hers, reading everything she didn’t say. His jaw tensed, and after a long moment, he nodded once — the smallest, saddest smile crossing his face.
“Thought so,” he murmured, voice breaking just slightly.
Then he turned and walked away, leaving her alone in the dim corridor with her heart racing and her entire world turned upside down.
The morning light cut through the Slytherin common room in soft, muted streaks — a sharp contrast to the chaos of last night. The air still smelled faintly of Firewhisky and smoke, abandoned cups and empty bottles scattered across tables.
Y/N sat curled on the emerald-green sofa, a half-finished cup of tea in her hands, trying to ignore the whispering headache pulsing behind her eyes.
Trying harder to ignore the memory of Theo’s lips on hers.
“Rough night?” Pansy asked, sliding in beside her with a knowing smirk.
Y/N didn’t look up. “Something like that.”
Pansy leaned in, lowering her voice. “So, how was it?”
Her head snapped up. “What?”
“Oh, don’t play dumb, Selwyn. Everyone saw it.” Pansy’s grin was positively feral. “The kiss. Nott. You. Fire. Passion. The whole room nearly combusted.”
Y/N’s stomach twisted. “It was— it wasn’t— Merlin, Pansy, it just happened.”
“Mhm.” Pansy sipped her pumpkin juice like she wasn’t dissecting Y/N’s life. “And yet you’re still blushing about it.”
“Sweetheart, you are literally the colour of a Gryffindor tie.”
Before Y/N could snap back, the portrait swung open and Theo walked in.
Conversation dipped instantly. Even Draco, who never missed a chance to mock anything resembling feelings, looked up from his breakfast.
Theo’s eyes met hers across the room — just for a second. Long enough for her chest to tighten, for the entire memory to crash back like a wave.
Then he looked away. Walked past. Sat at his usual spot near the fire, acting as though nothing in the world was different.
Y/N exhaled shakily, setting her tea down a little too hard.
Mattheo leaned over the back of the couch, grinning. “So… you two gonna talk about it or keep making the rest of us suffer through the sexual tension?”
Pansy snorted. “Please, they’ve been doing that for six years.”
Y/N groaned, standing abruptly. “I’m going to the library.”
“You hate the library,” Draco pointed out lazily.
“Then I’m going anywhere that isn’t here.”
She grabbed her bag and walked out, ignoring the smirks, ignoring the pounding of her heart when she passed Theo’s chair.
But as she brushed by, she caught it — the faintest whisper under his breath.
She froze, eyes flicking to him.
Theo didn’t look up, just turned a page in his book. To anyone else, it was nothing. But she knew him too well.
That wasn’t a name spoken casually.
That was a name spoken like a prayer he shouldn’t be saying aloud.
And suddenly, pretending nothing happened felt like the hardest thing she’d ever have to do.
Sixteen years of friendship — gone quiet.
Weeks passed in fragments:
A glance across the Great Hall.
An almost “hi” in the corridor.
An empty space beside her in Potions that used to belong to him.
It wasn’t anger keeping them apart. It was fear — that if either of them spoke, everything would spill out at once.
Their friends noticed first.
Draco and Mattheo started making “schedules,” deciding who would sit with who at meals so no one had to pick sides. Pansy rolled her eyes every time the group split up, muttering about how stupidly in love they both were.
And still, Y/N kept her distance — hoping time would untangle the knot that had formed the night Theo kissed her.
But time only made it tighter.
Late one night, Y/N sat curled in an armchair in the Slytherin common room, staring at the fire when her mother’s face appeared in the Floo.
“Darling! You’ve been quiet lately.”
Y/N tried for casual. “Just… school. You know. N.E.W.T.s. Chaos.”
Cressida Selwyn raised a perfectly shaped brow. “Ah. Or perhaps a certain Theodore Nott?”
“Oh, don’t mum me,” Cressida laughed. “Christina and I have been waiting years for this! He’s adored you since he was four, you know. Used to draw terrible stick-figure versions of you two getting married.”
“Christina showed me one just last week. She’s thrilled he finally found the courage to do something about it.”
Y/N froze. “Wait… he told her?”
Her mum’s smile softened. “He didn’t have to. She’s known her son longer than you’ve known yourself. Theo’s always looked at you like you hung the stars, darling. The only question is — are you ready to see it?”
And with that, her mother winked and disappeared in a swirl of green flame, leaving Y/N staring at the dying embers, heart hammering.
That same night, a parchment appeared on the notice board outside the common room.
Detention: Theodore Nott, Y/N Selwyn.
The classroom was dark except for a few flickering candles. Dust floated through the air as they scrubbed old potion jars, shoulder to shoulder in silence.
Every brush of his arm against hers sent sparks up her spine.
Theo’s jaw was tight, his usual calm cracked by the tension between them. “You’ve been avoiding me,” he said finally, his voice low.
“I’ve been busy,” she muttered.
“With everything except me.”
She froze, fingers gripping the cloth. “Theo—”
“I’m not sorry for kissing you,” he interrupted, eyes burning into hers. “I know I should be. But I’m not.”
The words hung between them, thick and dangerous.
She turned slowly to face him. “You can’t just say things like that.”
“Why not?” His voice was rough, quiet but furious. “You think I haven’t been losing my mind for weeks? You think sixteen years of pretending I don’t want you just disappears because I finally slipped up?”
Her breath hitched. “We’re supposed to be friends.”
“Yeah,” he said, stepping closer, “but tell me this still feels like friendship.”
She didn’t move. Couldn’t.
He was so close now that his breath brushed her cheek, his tie hanging loose, his hands still clutching the rag like he was trying to hold himself back.
And then — something in her broke.
“Fuck it,” she whispered.
She dropped the rag, grabbed his tie, and pulled him down until their lips crashed together.
The kiss was desperate — years of tension and unspoken want igniting all at once. His hands found her waist, pulling her closer as she deepened the kiss, the world spinning around them. The faint taste of soap and ink, the scrape of stone beneath their knees, the sound of both their hearts beating out of rhythm.
When they finally broke apart, breathless and wide-eyed, neither spoke for a moment.
Theo stared at her, lips swollen, voice barely a whisper. “We just broke the only rule we ever had.”
Y/N smiled faintly, still out of breath. “Then maybe it’s time we made a new one.”
If there was one thing sixteen years of friendship had taught Y/N Selwyn, it was how to hide things from Theodore Nott.
Unfortunately, that skill completely abandoned her the morning after she’d snogged him senseless in detention.
The sun hit the Great Hall’s long windows in a wash of gold as she slid into her usual seat beside Mattheo. The table buzzed with laughter and chatter, but she felt every molecule of awareness lock onto the boy walking toward her.
Theo looked maddeningly composed — hair a little messier than usual, tie slightly undone, that lazy grin that said nothing to see here.
But his eyes? His eyes found hers like they always did, sharp and knowing.
“Morning, Selwyn,” he said smoothly, dropping into the seat across from her.
“Morning,” she replied, pretending to be deeply fascinated by her toast.
Mattheo glanced between them, squinting. “Weird. Usually, there’s at least three insults by now.”
Draco looked up from his paper. “Or she’s threatening to hex him. Something’s off.”
“I’d say someone’s off,” Pansy chimed in, smirking.
Theo coughed into his juice. Y/N kicked him under the table.
“Ow— bloody hell!” He grinned, leaning forward. “Bit aggressive this morning, aren’t we?”
Her heart jumped. Don’t smile like that.
“I just don’t appreciate people implying things that aren’t true,” she shot back, cheeks pink.
Mattheo gasped, all drama. “You’re blushing, Selwyn.”
“Are too,” Pansy sing-songed.
Draco sighed, folding his paper. “Merlin, just admit something happened so we can all stop pretending you two aren’t one misstep away from snogging on the table.”
Theo smirked. “And ruin the suspense? Not a chance.”
Y/N nearly choked on her pumpkin juice. “You are impossible.”
He leaned closer, voice low enough only she could hear. “You didn’t seem to mind last night.”
Her head snapped up, eyes wide — and that was it.
Mattheo’s spoon clattered to the table. “I KNEW IT!”
The entire Slytherin table erupted into chaos — laughter, cheers, Pansy clapping like it was Christmas morning.
Y/N buried her face in her hands as Theo just sat back, grinning like the smug bastard he was.
“Oh, don’t act surprised, love,” Pansy teased. “You two have been making eyes at each other since nappies.”
Theo threw an arm around the back of Y/N’s chair, casual and infuriatingly confident. “Guess it just took detention to make it official.”
“Official?” she asked, looking up at him.
He smiled, soft and sure. “If you’ll have me.”
Her lips curved despite herself. “You already know the answer, Nott.”
Mattheo groaned. “Merlin save us all, they’re going to be unbearable now.”
Draco lifted his cup in mock salute. “To the worst-kept secret in Hogwarts.”
Theo’s thumb brushed her hand under the table — subtle, grounding, electric.
And for the first time in weeks, Y/N Selwyn felt like she could breathe again.
