pairing: ex!tomriddle x yn. slytherin!friendgroup x yn
summary: In their final year at Hogwarts, a tightly bound Slytherin circle navigates loyalty, power, and unravelling emotions. YN tries her best to push away any memory of Tom Riddle and their fractured past, but he refuses to let it stay buried. Between sharp wit and lingering obsession, some bonds prove impossible to break…
warnings: characters from loads of eras/fanfics, ex-boyfriend trope, bit of angst, bit of fluff, flashbacks, yn reader, fighting, possessive tom, jealous tom, slowww burn, yn lowkey hates mattheo ahhahaha
author's note: i've had the first 3 parts of this series in the drafts for a whileeee now. again, flashbacks are in italics
Morning in the Slytherin girls’ dormitory arrived softly.
A pale, silvery light filtered through the tall windows, casting long shadows across the stone walls. It was quieter here than anywhere else in the castle... thick, undisturbed silence that pressed gently against the air.
YN was awake before it. She always was.
There was something about early mornings she preferred. She liked the silence that blanketed her before the castle stirred, before voices filled the corridors, before she had to be seen. It gave her time to collect herself, to rebuild the composure she wore so effortlessly.
She pushed herself up slowly, brushing a strand of honey hair from her face.
There, resting neatly on her bedside table, was a folded piece of parchment.
She frowned. She hadn’t left anything there the night before.
Reaching for it, she unfolded it carefully, eyes scanning the ink—
You looked beautiful last night. As always.
Her breath caught. Her fingers tightened slightly around the parchment as her eyes flicked over the handwriting. It was elegant and clean, precise and controlled. Familiar.
She folded it up again, slower this time, placing it back down as if it hadn’t shifted something quietly inside her chest.
Behind her, Pansy groaned.
“If you’re already awake, I hate you.”
“Hate away,” YN replied, voice even.
Pansy rolled over, squinting at her. “Why do you look like you’ve already lived a full day?”
Changing the topic away from her, YN shot back, "I'm just shocked to see you in our dorm of a morning. Trouble in paradise?"
“You’re exhausting. There is no paradise.”
YN’s lips curved teasingly, but her gaze flicked once more to the parchment. A heavy feeling settling over her chest.
The Great Hall was already alive by the time they arrived.
Noise echoed against enchanted ceilings, plates clattered, voices overlapped; chaos in the most familiar way.
Their group slipped into their usual place at the Slytherin table like it had been waiting for them. Draco and Blaise immediately began arguing over something inconsequential, probably quidditch. Enzo was halfway through explaining something no one had asked about. Pansy picked at her food with mild disdain.
Theodore sat beside YN. As always.
“Did you sleep?” he said quietly, not looking at her.
“I did. However, I don't need to ask if you did, the matching eye bags with Mattheo tell me you were up on top of the astronomy tower all night... again.”
Across the table, Tom didn’t look at her.
Not directly. But somehow she felt it. That quiet awareness. That presence.
Like standing too close to something that burned, even when you couldn’t see the flame.
“It's not easy to sleep when your mind is elsewhere, is it, YN?” he said smoothly, cutting into his food.
No one reacted. But the words landed.
YN didn’t look up. She didn’t need to in order to know there was an evil smirk dancing across his lips.
Brushing him off quickly as though he didn't matter, YN turned to the rest of the group, "Merlin, potions first thing of a morning is cruel".
“It’s barbaric,” Pansy agreed immediately, abandoning her goblet with a dramatic sigh. “Who decided we should be expected to function before noon?”
“People with discipline,” Draco said coolly, dabbing at his mouth with a napkin, “so not you obviously."
“You don’t have discipline either,” Pansy shot back. “You have crippling daddy issues and a superiority complex.”
Blaise let out a quiet laugh. “Eh, those are the same thing for Draco.”
“Honestly,” Pansy continued, “if Slughorn expects anything remotely impressive this early, he’s setting himself up for disappointment.”
Mattheo stretched lazily in his seat. “I quite enjoy Potions.”
“Of course you do,” YN muttered, standing and smoothing down her skirt. “It involves fire, sharp objects, and the possibility of explosions. It’s practically tailored to your personality. Thank god you're not in our class.”
He grinned. “You're extra kind this morning, love.”
“I try my best,” she sneered, her face showing just how irritating she found the younger Riddle.
Lorenzo pushed himself up from the table, nearly knocking over his drink in the process. “Do you think we’ll actually make anything interesting today, or is it another one of Slughorn’s ‘subtle variations’ that all look identical?”
“They’re not identical,” Theodore said, rising beside YN. “You just don’t pay attention.”
“I pay attention,” Lorenzo protested.
“No,” Blaise cut in, “you watch. You're not even smart enough to know what you're meant to be paying attention to. There’s a difference.”
“That doesn’t make you right,” Blaise replies in a sing-song voice.
YN let out a soft breath through her nose, a smile tugging at her lips as the group began to move.
The corridors were already filling. Students spilling out of the Great Hall, voices echoing against the stone walls, footsteps overlapping in a steady rhythm. Pansy slipped easily into step beside YN, looping her arm through hers without asking.
“If Slughorn pairs me with someone incompetent,” she said, “I’m leaving.”
“You say that every year, so I’m betting won’t,” YN replied.
“You’ll complain, and then you’ll stay.”
Pansy tilted her head. “You know me too well.”
“It’s a burden I carry gracefully.”
Theodore walked on YN’s other side, hands tucked into his pockets, gaze forward but attention unmistakably on the conversation.
“Can't be worse than last year,” he said “, Looney Lovegood. I had no chance of ever scoring higher than an Exceeds Expectations.”
“Merlin, she's dreadful, but don't act like you were ever destined for more than an Exceeds Expectations,” YN mused.
Behind them, Draco and Blaise continued their quiet back-and-forth, Mattheo occasionally interjecting with something entirely unhelpful, before he turned off to head toward his own class.
As they walked through the door, the smell hit first. Sharp and metallic in a way that gets stuck at the back of your throat. The second thing to hit her was the colour. Red. 'Great, 2 hours with the Gryfindors, ' she thought.
Cauldrons gleamed under low light, ingredients neatly laid out along the benches as Slughorn beamed at them from the front.
“Ah, my favourite class,” he announced, spreading his arms as though welcoming honoured guests. “Final year already, where does the time go?”
“Mercifully fast,” Draco muttered under his breath.
“Take your seats, take your seats! Come in, everybody, right up to the front, that's it!”
The group dispersed, slipping into their usual places without needing to think about it.
YN sat beside Theodore. Pansy on her other side.
Slughorn clapped his hands together. “Now then. Today’s potion requires precision, patience, and, most importantly, chemistry between partners.”
A few groans echoed through the room. He smiled wider.
“So, I’ve taken the liberty of assigning pairs.”
YN felt it before she heard it. That quiet shift in the air. It's almost like that nutter Trewlaney had rubbed off on her, because she knew, deep inside, what was coming next.
“Miss YLN… Mr Riddle. Two of my best students, there we go up here to this bench, please.”
The Slytherin group reacted exactly as expected. Pansy’s head snapped toward her. Draco smirked, nudging Blaise, whose expression shifted into something quietly entertained. Lorenzo let out a low whistle. Theodore tried to meet her eyes, but YN didn't look anywhere but straight ahead.
She remained still for half a second longer than necessary.
Then she stood. Composed like being in close proximity with Tom for the next two hours didn't make her heart flutter and her stomach drop in dread at the same time.
“Try not to murder each other,” Pansy murmured.
She turned and walked to the new bench. Tom was already there waiting with this irritatingly smug look on his face. But he didn’t say anything as she approached.
To be honest, he didn’t need to. Everything between them had always existed in the space before words. So, YN set her things down carefully, fingers steady despite the quiet tension curling beneath her skin.
And for a moment neither of them moved.
They sat in still like statues, their chests barely rising and falling as they waited for Slughorn to pair off the rest of the class.
Then, in perfect synchrony, they began.
Ingredients were measured without discussion. Movements aligned instinctively. There was no hesitation, no awkwardness in the mechanics of it.
Like nothing had changed.
“You’re rushing the second stir.”
Her jaw tightened. “I’m not.”
She didn’t respond, but her movements slowed, just slightly.
“You always do when you’re more focused on reading than stirring,” he added, voice quieter now.
Her grip tightened instinctively.
There they stood in an empty classroom. YN had been panicking about the potions practical, so Tom snuck her out past curfew to help her.
“You’ll ruin it if you rush,” he murmured behind her, voice low, almost amused.
His hand closed gently over hers, guiding the motion to be slow, deliberate.
The other rested at her waist, pulling her so close that she could feel the warmth radiating off his body.
“Then stop distracting me,” she muttered, though she leaned into him just slightly with a soft smile.
“I’m helping you. Think of me as your tutor.”
“I, of all people, do not need tutoring.”
“I know you don't need it, but you like it,” he whispered as he kissed her cheek.
The present snapped back into place as he gripped the top of the spoon, half of his hand closing over hers.
YN inhaled softly. She couldn't help it.
They hadn't been that close since they broke up 4 months ago. She wanted to scold him, push him away, tell him to give her space. But his smell was intoxicating, and before she could stop herself, it slipped out, “Tommy—”
Her entire body went still, and silence followed.
Tom didn’t move for a single count before resuming stirring, likely not wanting to mess up the potion. His hand remained steady over hers, guiding the motion of the spoon as if nothing had changed.
But still, she could tell that something shifted. Something subtle yet dangerous. Like she had just lit the fire beneath him without realising.
In that single word, something old had resurfaced. Not the arguments. Not the tension. Not the fractured ending they both pretended to stand by.
Something before that. Something he had refused let go of.
Tom’s gaze stayed locked on the cauldron, but his mind ran elsewhere. She had said it without thinking. That meant it still lived somewhere inside her.
Buried, perhaps. Ignored. Suppressed. But not gone.
For months, he had tolerated the distance. Let her play at detachment, let her convince herself that she had walked away cleanly, that whatever they had built could simply be… ended.
He had allowed it. Not because he believed it, but because he knew she would break. He knew that she would come back.
But then summer passed, and she hadn’t. So now, when he saw the opening, his hand shifted ever so slightly against hers, not enough to be obvious, just enough to remind her it was still there. Still guiding. Still in control.
He didn’t look at her. For the first time since the break, something in him settled. Something of a certain clarity.
They were not over. They never were. And now he knew exactly where the cracks were.
But in the parts of her that still remembered him without trying.
Tom had never been sentimental. He didn’t believe in chance, or fate, or whatever nonsense people used to justify their lack of control.
And this... it was something entirely different from that nonsense.
She had built something around him once. Something close enough to reverence that it blurred into devotion.
And she thought she could simply dismantle it? No.
His jaw tightened slightly, the faintest shift in his expression, gone as quickly as it came. He would not chase her, he would not beg, but he sure as hell was not going to let her walk away.
So he decided right then and there, his large hand still engulfing hers, that he would remind her. Carefully. Precisely. Patiently. In every way that the world would allow him, Tom would be a force she could not ignore.
He would place himself back into the spaces she thought she had cleared. Into her routine. Her thoughts. Her instincts.
Until she stopped resisting it. Until she stopped pretending that she was done with him. And when she finally realised that, when she came back to him, we would be waiting exactly where he had always been.
YN pulled her hand out from under his and turned away quickly, focusing on the potion with sudden intensity, her pulse louder than the bubbling cauldron. “Pass the valerian root,” she said, too composed.
He handed it to her without a word, but didn’t look away.
Herbology was their next class. YN walked beside Theodore and Pansy, her posture composed, her expression neutral. If either of them noticed the slight tension still lingering in her shoulders, they didn’t comment on it.
“That was unnecessarily stressful,” Pansy said, brushing a strand of dark hair over her shoulder.
“It was day one,” YN replied.
“Well count me out for day two .”
Theodore let out a quiet laugh, running a hand through his hair. “At least you didn’t have to deal with whatever that was,” he said, nodding vaguely behind them where Tom strode alongside Blaise. “Slughorn looked like he was about to cry from pride.”
“He probably was,” YN muttered. “He lives for that sort of thing.”
“Of course he does,” Pansy said. “It’s the closest he’ll ever get to actual achievement.”
“Ooh, harsh… but true,” Theodore added.
They stepped into the greenhouse, warmth immediately wrapping around them again. It smelt of damp earth, crushed leaves, and something faintly sweet. It was a welcome change from the thick, metallic heat of the dungeons. Rows of plants lined the space, some twitching slightly as students brushed past them.
“Right then!” Professor Sprout called from the front. “Pairs today, same as usual!”
YN barely had time to set her things down before Theodore dropped his bag beside her.
“Lucky you,” he said lightly. “You get me.”
“How will I cope,” she replied dryly.
“You won’t. You don't. But I’ll carry us as always.”
She huffed a sarcastic breath, reaching for the gloves laid out on the table. It was easy with Theodore. Effortless in a way that didn’t demand anything from her. They had been best friends since they were babies. She had never lived a day without him by his side, and in a way, he was the brother she never had. The whole group shared a similar sentiment; it wasn't easy being the only child in the houses they grew up in... having everything placed on your shoulders alone.
“Don’t pull too hard,” Theodore added, watching her reach for the plant. “You’ll snap the root.”
"Yeah, ok Mr Exceeds Expectations. I know what I'm doing, I’m always right.”
A voice cut in before she could respond.
He stood at the table beside them, sleeves rolled slightly, expression calm, composed like he hadn’t just inserted himself into a conversation that didn’t involve him.
“You will damage the root if you twist it like that,” he continued, eyes on the plant, not on her.
Theodore looked triumphant. “Told you so.”
YN kept her attention on the plant, her fingers adjusting slightly despite herself. “Whatever, I had it under control,” she said.
By the time they left Herbology, the sun had shifted higher, heat settling more heavily over the grounds as they made their way back toward the castle.
The noise had returned to the Great Hall.
YN dropped into a seat between Theodore and Draco, exhaling softly as plates filled in front of them. The noise was welcome now, something to drown out the constant hum sitting just beneath her skin.
She noticed it as she leaned back. A jumper draped over the back of her chair.
Dark. Familiar. Her fingers brushed the fabric briefly as she caught a whiff of the scent she knew too well.
“That yours?” Theodore asked, glancing at it.
She didn’t move it. "Uh, no... no it's not.”
Arithmancy passed quietly. Too quietly.
None of her friends sat near her in this class. So it should have been easy to focus.
Numbers lined the board. The professor spoke in a monotone that blurred into the background. Rows of students, heads bent over parchment, the scratch of quills the only real sound in the room.
She followed the professor's instructions and flipped to the next page of the book, and something slipped out onto the desk.
Another piece of parchment. Her breath caught as her eyes darted around the classroom. No one was looking at her, not even in her general direction.
You make everything look effortless.
Her fingers tightened slightly around the page. This wasn’t coincidence.
In a striking contrast, Defence Against the Dark Arts was anything but quiet. Magic cracked through the air sharp bursts of light cutting across the room as pairs moved through drills. Voices overlapped, instructions shouted, magic colliding in controlled bursts.
YN moved easily, wand steady, movements precise. She had a natural knack for combat and didn't even need to think.
Across the room, Tom mirrored that same control. Effortless and calculated.
For a brief moment, their eyes met and something passed between them. Not cold like this morning or gentle like in potions. But rather something she wished wasn’t familiar.
They stood in an empty corridor. It was late. Far too late for either of them to be out of bed, but neither of them cared. The torches along the walls flickered violently, casting sharp shadows that seemed to stretch and twist with every movement.
“Lower your wand,” Tom said, voice cold, controlled.
“No,” YN snapped, her grip tightening. “Not this time.”
“You’re being irrational.”
“I’m done letting you control me,” she shot back, her voice breaking despite herself.
His jaw clenched. “You don’t get to decide that.”
A harsh laugh escaped her, wet with frustration. “Of course I do. That’s how this works, Tom.”
Something dark flickered behind his eyes. “Lower your wand,” he repeated, slower this time.
“Or what?” she challenged, her chest rising and falling too quickly. “You’ll make me?”
A moment in time passed. Then—
The spell shot from her wand in a burst of light, fast and precise, forcing him back a step, but not enough.
He blocked it effortlessly.
“Is that what you think this is?” he said, almost amused now, circling her slightly. “A duel?”
Her eyes stayed strained on him as tears spilt down her cheeks. He looked at the girl in front of him, and he thought she looked pathetic. She was always so composed, so sure of herself, so in control. But now...
He scoffed, "Please, YN, save the dramatics. You never follow through.”
The words hit harder than any spell.
“You say you’re leaving,” he continued, voice lowering, more dangerous now. “You say you’re done. Merlin, how many times have I heard that one from you? And yet there you are. Still here. Still arguing. Still—”
“Because you don’t let me go!” she shouted, her voice cracking as the tears began to blur her vision. “You don’t stop, Tom.”
“Why would I?” he cut in sharply. “Why would I stop when I have you under my control, doing everything I say…”
Silence fell for half a second. Heavy and suffocating, causing her chest to rise more frantically. His gaze locked onto hers, something intense, unrelenting, almost consuming in the way he looked at her.
“You’re not something I just… lose interest in,” he said, quieter now. “You don’t walk away from me because you’re frustrated.”
Another spell shot from her wand, reckless this time.
He deflected it instantly. “Stop,” he said.
“Stop this,” he repeated, stepping closer.
“I hate you,” she managed to choke out through the sobs.
Something in his expression shifted, but it wasn't what she wanted to see. His face wasn't laced with hurt, his voice wasn't laced with sadness.
All he showed was dismissal. “No. You don’t.”
The words landed like a verdict.
“You don’t get to tell me how I feel,” she said.
“I don’t need to,” he replied. “I know.”
Tears slipped down her cheeks and down her neck.
“I’m trying to leave you,” she said, quieter this time. “Why won’t you just let me?”
Tom stepped closer. Grabbing her wand and throwing it to the floor, disarming her in a lazy effort, proving his point that in fact she could never follow through.
He was now close enough to lift his hand out and tilt her chin up so she had to look at him. The weight of his presence pressed into her space like it belonged there. Her breath hitched.
“You think this is you walking away?” he continued, his voice softer now, almost coaxing. “It’s not. It’s you panicking because you don’t understand it.”
“I understand perfectly,” she whispered.
“No,” he said. “You don’t leave something like this. Not when it’s real.”
Her eyes searched his, desperate, uncertain.
“And this is real?” she asked, her voice barely there.
By the time dinner arrived, exhaustion had settled into the edges of everything. The Great Hall buzzed louder than usual, students talking over each other, energy uneven and restless.
YN sat back in her chair, rolling her shoulders slightly as plates appeared in front of them.
“I’m already done with this year,” Pansy announced.
“It’s been one day,” Blaise replied.
“And it’s been exhausting.”
Before she could respond a rush of wings cut through the noise.
One landing in front of YN.
“Oh, this is interesting,” Draco said, leaning forward.
“Open it,” Pansy demanded.
YN reached for the letter, breaking the seal carefully, her expression unreadable as her eyes scanned the parchment.
Across the table, Tom had already opened his. “Head Boy,” he said simply.
“You’ve got to be joking,” Mattheo laughed.
“This will be insufferable,” Enzo added.
“No,” Draco corrected, watching the two of them carefully, “this will be entertaining. Fate sure has a sense of humour.”
YN looked up, but Tom was already looking at her.
The letter detailed that there would be a meeting on the third floor this evening after dinner.
So that's where they were headed.
The corridor was quiet with all the other students still in the Great Hall. Their footsteps echoed softly against the stone and for a while, neither one of them spoke.
Then, slicing through the tension, “We always did work well together.” The words landed lightly, almost conversational. Like he was recalling something harmless. Something simple.
Her jaw tightened. “Don’t.”
He didn’t react. He didn’t so much as glance at her.
“If you’re going to spend the year trying to ignore me,” he continued, tone steady, measured, “you’ll find it exhausting.”
“Will you?” he said softly, but not kindly. He was pushing her buttons, and he knew all the right ones to press. “You never were very convincing.”
The meeting itself was brief.
Instructions. Responsibilities. Expectations.
Late patrols. Shared duties. Time spent together whether they liked it or not.
The walk back to the common room felt longer.
“You know… it’s almost funny.”
She didn’t look at him. “What is?" her tone was bored.
“How everything keeps putting you back beside me.” Her fists clenched slightly at her sides. “Almost like it knows something you don’t.”
She stopped walking. Just for a second. Then continued, refusing to give him the satisfaction of an answer.
The common room was already full when they returned. Voices, laughter, the familiar low hum of Slytherin settling in for the night.
“Well?” Pansy demanded immediately.
“Extra points for Slytherin this year? Finally, a chance to win the House Cup?” Lorenzo added.
“Unlikely,” YN said, “Look at the idiot you're sitting beside. For every 10 points we get, he loses 50.”
They all laughed, knowing, unfortunately, that was true. Ever since Mattheo was sorted into Slytherin, they had no shot at winning the House Cup.
YN moved toward her usual seat, lowering herself into it with practised ease as she began to recap the night's meeting for her friends and informing them of the other Head Boys and Girls.
Tom didn’t sit beside her. But he didn’t sit far either. And somehow that felt worse.
Later, in the quiet of her dorm, YN sat on the edge of her bed, the castle finally still. She got dressed for bed in silence, ridding herself of the longest first day of school in history.
Pansy wasn't in the dorm yet, go figure.
She slid under the heavy green quilt, immediately cuddling into her pillow when she felt it... Another note under the white pillowcase.
Her breath slowed as she unfolded it.
Her heart began to pound.
Silence filled the room. She knew who the notes were from. Though it wasn’t his handwriting they were his words.
All of a sudden she was hit with a piercing pain in her head, as memories overtook her. Stolen glances, delicate touches, late night trysts and kisses understand the civets. And for the first time since ending things, she didn’t know if she wanted to prove him wrong. She couldn't stop the thoughts spiralling in her head.
They didn’t feel like her own. Not entirely anyway. She couldn't control what she was seeing or the feeling they were bringing up.
She began to feel nauseous at the speed of her own mind. Dissoriented as memories flashed before her eyes. Her breathing was picking up, she felt like the walls were closing in around her.
And then suddenly it all stopped. Her breath slowed.
In place of the confusion, anger overtook her as a cold realisation settled.
The feelings, the memories, the helplessness... they were placed carefully. Intentionally.
Tom was inside her head, playing with her like some doll.