Prompt from BrytteMystere: Could you make a Potterlock fic with Molly as Moriarty's sister, in Slytherin with him (dark!Molly, PLEASE) whilst snogging the Ravenclaw Muggleborn (his father was a Muggle) Sherlock Holmes?

I apologise that this has taken so long, but your reward for waiting is plot: congratulations. ;) I may have taken liberties with 'snogging', but I hope you like it.

Trigger warning of a bit of torture in this, and if you're a Harry Potter fan then you can probably guess in what form.

Jim Moriarty circled the desk in the middle of the room, smirking at the boy sat in one of the chairs.

He nodded approvingly towards the girl in the corner, her brown eyes resembling his own even if they were missing the manic glint that had made so many others beg for mercy.

The exception sat before him, but Jim promised himself that the tight binds that kept Sherlock Holmes in place would remain until he was an exception no longer.

'Is she staying?' Sherlock broke the silence, his voice carefully controlled.

Jim gripped the back of his hair, resting his chin on the other boy's shoulder as he directed both of their gazes at Molly Hooper, beautifully frozen and the only other person in the room, which most of the Castle didn't even know existed.

'Of course,' Jim murmured, grinning at his sister as Sherlock winced. 'This is her reward, Sherlock, for bringing you to me.'

xxxxxx

Molly jolted awake when the door slammed, and she opened her eyes to find her brother standing at the foot of her bed.

'How the fuck did you get up here?' She tried to control her pulse; her sheets tangled around her legs as pulled herself back from the edge of the bed.

'What? That ridiculous enchantment to stop boys from coming up to the girls' dormitories?' She nodded blearily. 'Don't insult me, Molly. I need a favour.' She rolled her eyes, pulling out a dressing gown from the wardrobe and passing the empty beds of the girls who shared the room with her. They were all at the Quidditch match that Molly deemed a waste of time, and her failure (even though Molly viewed it as quite the opposite) to endear herself to them meant they had left that morning without bothering to wake her.

'No,' she said breezily, recalling the last time she'd helped him, which had resulted in the ruination of her favourite dress and a month's detention. 'Get Seb to do it.'

'He's an imbecile,' Jim replied distractedly, flicking a speck of dirt from his under his nail as she washed her face at the sink in the corner.

'He's your best friend.' She countered calmly, disappearing behind the screen beside her bed to change out of her pyjamas.

'I don't have friends,' Jim reminded her, and she scoffed, pulling a worn t-shirt over her head.

'No, you have one sister who does all your bloody work for you.'

'Exactly. So…'

'No.' She came back into view, tying up her hair in its standard ponytail, a clip held between her teeth. 'Do it yourself.' She was the only one who could speak to him so insolently, and it was something she took through advantage of.

'Haven't you ever heard of the element of surprise, dear sister?' She paused to study him, her eyebrows raised to discern how important this favour was to him.

'What do I need to do?' She asked warily, stopping him before he supplied the answer. 'I haven't agreed yet. I just want to know what I'm signing up for.' He grinned knowingly, aware that he'd already won half the battle.

'I want to have a word with someone. They're getting in my way, and I want them to leave me alone.'

'Who is it?'

'Sherlock Holmes.' She pulled a face, slumping onto a nearby chest as all interest was sapped from her, something Jim immediately attuned to. 'Come on, Molly. I just need you to tell him where to go, and then I'll do the rest.'

'I'll take great pleasure in telling him where to go,' she muttered darkly, causing Jim to chuckle.

'Please, Molls.'

'Well, for a start, I don't believe that you only want to talk to him,' he grimaced in acceptance of her point, and she shrugged. 'If you want my help, I have a right to know.'

'Fine. But I can't explain it all to you now,' he sighed, 'you can stay during the meeting, see what Holmes has to say,' she started to argue, but he held up his hands to stop her. 'That's the deal, Molls. Take it or leave it.'

She scowled, and he grinned triumphantly.

'All right, I'll do it,' Jim rose to leave, his smirk well established on his face. 'But if you fuck me about, Jim, I'll tell Holmes that you cried yourself to sleep every night for a week after Mum threw away your teddy.'

He knocked the snow globe off her bedside table with his wand as he walked away.

xxxxxx

Her reward.

'Maybe a gift card would have been better,' Sherlock murmured, and Jim laughed manically, the sound echoing through the room as he placed himself casually in the other chair.

'You know, I think she prefers this,' Jim grinned, leaning back to face his sister. 'Don't you, Molls?'

Her eyes were locked on Sherlock's as she gave a sharp nod, and his gaze lingered on her even as Jim resumed speaking.

'But you know why you're here, Sherlock. You've been very bad, sticking your nose where it doesn't belong.' Sherlock's face became a mask of innocence, and Jim smirked at this deliberate change. 'Or am I to believe that Peter Crawford escaped from the Shrieking Shack on his own? Or that your dear brother was merely passing the out-of-order toilet on the sixth floor at the very moment when Alistair Coyle was about to disclose the password to Professor Barnes' office.'

'Well maybe you'll have to ask him about that,' Sherlock's eyes blazed, and Molly hated that it still affected her, that it reminded her of the one unutterable truth about her and him.

She wasn't weak, but even the strongest of people had one area of vulnerability.

Sherlock Holmes was hers.

xxxxxx

'I think your brother did you a favour.'

He'd murmured the words from the darkness, emerging out of the shadows with mussed hair and a loose tie on the one night that she was most in danger of giving in to what she'd suppressed for nearly seven years.

'Tom Knight? Really?'

She was angry first, bristling at the insinuation that Jim had in some way been right to intimidate her boyfriend into dumping her, wondering vaguely how he figured out what had caused Tom to run fearfully away from her at dinner.

'Leave me the fuck alone.' Her voice trembled, so consumed by anger that she missed what it meant when her pulse quickened and her throat constricted.

'You must have known he was an imbecile. I simply cannot fathom what would possess you to-'

She lunged for him, pinning him to the wall with her wand while he smirked down at her, incensing her enough that the words tumbled out of her mouth unprompted.

'What would you know? You're nothing but a pathetic virgin.'

She knew she'd hit his pressure point, his nostrils flaring as she craned her neck to look at him, so wrapped up in her own triumph that she failed to stop his lips as they crashed onto hers.

His mouth took hers with bruising force, but she recovered herself desperately to limit his upper hand, her tongue battling fervently with his even though she couldn't remember what they were fighting for.

But just as quickly as he'd begun, he wrenched himself away, leaving every nerve ending in her body charged as she gasped in oxygen.

'Say it again,' he snarled, his grip punishing on her hips, and later, she would be able to identify the sharp crunch that was her resolve breaking.

'Virgin,' it was barely above a whisper, but when he pulled her to him again, she knew that he'd heard it.

The sensation was like that of a Portkey, her insides twisting as his hand skimmed down her side, while she tugged on his hair in a frantic attempt to anchor herself. Every flick of his tongue proved his point, and her anger at this collided with the lust coursing through her veins, dulling her reason as she allowed herself to be thrust against the wall.

The brick scratched through the thin material of her blouse as he hoisted her legs around his waist, but she welcomed the discomfort, staving away tenderness and gentleness and anything that could neutralise this conflict between them.

She thrashed her head back when he tore his lips away, his teeth instantly attacking the soft skin of her neck, leaving dark marks that would fade even after she'd forgot what it felt like when they were made; and she'd skip the part where he carried her into a classroom, focused on his fingertips on her inner thighs and his impatience as he rucked her skirt around her waist.

She whimpered, biting her lip to quell the noises that she began to make, adamant that she wouldn't allow him the victory of hearing her come undone.

But there was nothing she could do to stop him from seeing it: the way she threw her head back when his hand brought her release, a silent scream screwing up her face as tendrils of hair stuck to her neck from perspiration. Sherlock traced a strand with his thumb, but she diffused the affection by ripping open his belt buckle, murmuring her approval as he dragged her roughly to him in response.

He drew her knickers down her legs, and slipped them into his pocket before he let his trousers fall to the floor. She snuck her hand into his boxers and encircled him, his hissed exhalation hot against her cheek as she pumped experimentally, freeing his cock from his pants when he squeezed her hips imploringly.

'Doesn't… change… anything,' she whispered, and she shut her eyes to protect herself from the penetration of his gaze even as he lined himself up with the slit of her sex.

'I know.'

His voice was low as he thrust inside her, their moans muffled against each other's skin, her nails digging into his shoulders as she urged him to go faster.

It was artless, the way they'd moved against each other; but she wouldn't be able to describe it as sloppy even after, when every fibre of her being wanted her to denounce him as the most unskilled shag she'd ever had.

In truth, she'd never felt tremors running the full length of her body before, and no other boy's touch had left a fiery brand on her skin long after his fingertips had moved elsewhere.

For a moment, it had been too much: his teeth on her bottom lip, his hand burning through her clothing as he cupped her breast, the muscles on his back rippling under her fingertips as he plunged into her for a final time, holding her together as she crumbled before him.

She realised what they'd done when the chill in the room hit her exposed legs, and he stumbled away from her, ruffling his hair convulsively once he'd secured his belt.

She resisted the urge to apologise, reminding herself that he had intruded on her; but the word that had acted as trigger sounded tauntingly in her head, and she blushed at the fact that she had said it.

The traces of them were removed with a flick of her wand, slight wrinkling of her shirt the only physical evidence that anything had passed between them.

But in the safety of her bed after, sleep out of reach, Molly knew that it would take more to eradicate the ghost of his grip on her waist, the feeling of his scent surrounding her, and the softness in his eyes just before she came, as if that very look had pushed her over the edge.

xxxxxx

Jim stirred his tea slowly, his finger suspended in the air above his cup, and Molly marvelled in her brother's ability to make even the simplest of actions look sinister.

'Where's brother Mycroft now, Sherlock?' Jim murmured into his drink, baring his teeth as the scalding liquid eased down his throat, welcoming the burn that it left in its wake. 'Hmm? Will he burst through the door to save you? I think you'll need it.'

'I have no idea why you'd think I'd work with my brother,' Sherlock said icily, and for a moment, Molly felt that she was invisible, watching the conversation from behind a screen. 'I can assure you that Professor Holmes and I do not get on.' He hissed out his brother's title, and Molly would have been surprised that his bitterness had been laid so bare if she wasn't sure that this revelation was wholly calculated.

'Then why would he accept a job here?' Jim countered, a cold smile on his face. 'Why would he have gone out of his way to protect a brother he despises?'

'He is not here to protect me,' Sherlock replied thunderously, but this time Molly wasn't so sure that his rage was deliberate.

'Touched a nerve?' Jim voiced her suspicions, the answer given in the way Sherlock snapped his mouth shut. 'I can just picture you running home to tell brother Mikey that a boy at school was scaring you,' his grin is primal, his eyes flickering with the hint of insanity that Molly told herself she was imagining. 'Did you cry when you begged him to fight the bully for you?'

Sherlock's eyes burned with all the fire that their aqua blueness could muster, and Molly felt a crawling sensation up her spine when his anger spread through the room as a tangible current.

'You can bait me all you like,' Sherlock said through gritted teeth. 'I will not give you what you want.'

Jim smirked, his wand floating from his lap even though it was well within his grasp, appearing weightless, innocent; in sharp contrast of what they all knew it was capable of.

'We shall see,' the words were exhaled out of Jim's lips with the same ease: the calm before the proverbial storm, the storm they all saw coming long before the wand tip was pointed at Sherlock.

His face contorted with pain as Jim muttered the incantation, writhing against the bindings as the curse took hold, each second more excruciating than the last.

Molly relied on the wall to keep her upright, and she was glad for a second that Jim didn't look back to gauge her reaction, before she realised that it was because he was enjoying this too much.

She felt sick when she remembered she'd promised to enjoy it too.

xxxxxx

Molly nearly shrieked when she was pulled out of the corridor, a hard body frogmarching her into an unused classroom, pinning her against the wall.

'Are you looking for trouble?' She hissed, her anger abating somewhat when a pair of lips covered her own, and she sank her fingers into the soft hair of her attacker.

'Why? Do you know where I can find some?'

Sherlock Holmes loomed over her, his slight breathlessness matching her own as he slid his hands down to cup her arse, smirking cheekily when she yelped in surprise.

'Bastard,' the corners of her mouth edged up slightly. 'What is it now?' He shrugged, splaying his fingers under the back of her shirt, the tips pressing into her heated skin.

'Bored,' he muttered, before he drew her mouth to his again.

'Sherlock,' she gasped out his name as he began to place kisses along her jaw line. 'Jim wants to-' The reaction was instantaneous, and she whined at the loss of him when he went to lean on the windowsill across the room.

'What did he say?' His voice was different too, and she bridled at the hardness that had seeped onto his features.

'That he wants to meet with you, and I have to organise it.' She tried to communicate her irritation, but he turned away, his hands tenting under his chin in the manner of his that annoyed the hell out of her.

'Why you?'

'Why not me?' She replied haughtily, but he was oblivious to her offence.

'Don't be childish; that wasn't what I meant.' Her mouth formed a tight line, and she braced a hand on the doorknob.

'Forget it. I have to go,' she began, but he swivelled to lock his eyes onto hers, keeping her in place.

'No, you don't. Did he say why he wanted to meet me?' She rolled her eyes, feeling more like an informant, in a situation out of her control, with each passing moment.

'He wouldn't say,' he stared her down, and she realised that he was trying to work out whether she was lying, trying to decide whether he should trust her even after she'd risked her brother's wrath by continuing whatever this was.

'Next time you'll have to get it out of him.'

'Next time?' Their voices were rising, and she could see the confusion that swept into his eyes as the situation barrelled out of their control. 'I'm not here to get your information for you.'

'Then why are you here?'

For a moment, he looked just as surprised as her that the words had left his mouth, but now they had been uttered he couldn't- perhaps wouldn't- take them back.

She felt sick, the nausea like a side effect of wasp venom, the stings making her skin itch in all of the areas vulnerable to his gaze.

Her hand closed around the doorknob, but she paused before she twisted it, giving herself the last word because she couldn't have her dignity.

'I hope he destroys you,' she said, her voice trembling with rage, meeting his eye a final time, 'because I will savour every moment of watching you fall.'

xxxxxx

Sherlock's body shook even after Jim took the curse away, his body slow to catch up with the fact that it wasn't supposed to be in pain anymore.

Molly's back was pasted to the wall as she tried to distance herself from the table, desperate to deny that the boy with his back to her was the brother who had protected her for as long as she could remember.

She watched Jim take another casual sip of tea, blanching at the swilling noise that he made when the liquid passed his lips, as if he was bored of waiting for Sherlock to recover.

'No,' Sherlock rasped, his eyes hollow as he stared at Jim from beneath his disturbed curls.

'Oh, Sherlock, what is the point in trying to fight?' Jim leaned forward conspiratorially, and Molly winced at his attempt at a genial tone. 'Tell me where you get your information from and I'll leave you alone.'

Molly froze, bile rising in her throat when she realised that she was the answer to Jim's entire question.

'No.' Her eyes searched Sherlock's, fear etched on her features at how easily he could give her away if he wanted to.

Jim screeched, and raised his wand again, the curse spewing out of his wand non-verbally this time as Sherlock succumbed to the suffering once more.

Molly tried to shut her ears to Sherlock's screaming, but the sound pervaded even the hands that she clamped either side of her head, incoherent mumblings looping maddeningly in her brain.

It hurt her to see him in pain, so unbearable that she folded in on herself, powerless to save him, wishing he would just give Jim the information he needed so that it would stop.

'Molly,' her name toppled out of Sherlock's lips, and for a moment it was only her who heard them: for a moment she was the only one to know that her own downfall had arrived. 'MollyMollyMollyMolly.'

She watched stricken as Jim's eyes moved frantically from her to Sherlock, silent tears roving down her face as she was exposed as the source of all of Sherlock's information, silently begging that Jim would hurt her instead.

'Molly. I love Molly. Molly. Love Molly. Mine. Molly.'

Her eyes snapped to Sherlock.

He rocked backwards as much as the bindings would allow, so absorbed by his agony that he seemed to have forgotten that there was anyone else in the room at all, that he had no idea that anyone else could hear the professions pouring so readily from his mouth.

Jim looked poised for something, and cold fear gripped her at when it occurred to her that this was what he had done even without the knowledge that Sherlock was involved with his sister.

So she drew her wand, her thoughts blurring in her head until she managed to cling onto the one thing that she needed most of all in this moment.

Silence.

She couldn't even remember what it sounded like as she drew her wand, pointing it at the one person in the room who was to blame for all of this noise, red light blinding her as it spewed from the implement in her hand.

xxxxxx

There was a dull throbbing in her head when Molly woke, and she nearly fell out of bed when she opened an eye to find that she was not in her dormitory.

Her stomach began to drop when she rolled onto her back, the sheets rubbing against her bare skin when it became clear that she failed to put on pyjamas the night before.

A pair of blue eyes met her own when she'd maneouvred herself onto her side, and she lost herself in them for a moment before she shook herself, running a hand over her face in exasperation.

'It happened again?' She groaned, irritated when all she got was a chuckle in response.

'I'm afraid so,' she shuddered as the early hour leant his voice a husky quality, and she cursed him when he laughed again, to show that he had noticed her reaction.

'At least I was drunk this time,' she bathed in this fact for a minute before she noticed that he was silent, taking in his bashful expression with increasing horror. 'No no no. No. But- I have a headache,' she said desperately.

'Well… You may have hit your head,' he replied slowly, and her eyes slipped shut momentarily when she asked how. He coughed, and she grimaced when she followed his hand to the headboard, his fingers curling around one of the curved metal bars.

She reached up to probe the burgeoning lump at the back of her head, and was surprised when he edged closer to feel it too, his bottom lip between his teeth as he looked at her in concern.

'Does it hurt?' He murmured, and she felt her mouth go dry as she shook her head.

The events of the previous night began to come back to her, including, in her defence, a party, even though she had admittedly been nearly sober when she dragged him out with her.

She seemed to remember that watching him dance with Kasey Frost had played a part in them ending up here, but in the light of day she couldn't imagine why that should upset her so.

Molly could feel his gaze on her, and she flicked her eyes to his, discomfited when she found something that she couldn't quite name within them.

'Well, sorry about this,' she said slowly, beginning to roll away from him, 'it won't happen again.' She almost made it out before his hand gripped her arm, pulling her back onto the pillow with a leg flung over hers so that she wouldn't be able to escape.

'Molly,' she bit her lip, 'you said that the last time.' She sighed, a cursed inner voice reminding her that she had said it the time before as well. 'Don't you think we should be honest with each other?' She inhaled sharply, and would have tried to run again if he hadn't been pinning her in place.

'I… I don't know what you mean,' his facial expression told her that she was being tiresome, and she hoped that he would give up.

'It is clear that you are in some way attracted to me,' she scoffed, but fell immediately silent when he looked at her rather pointedly, 'and I don't see why you should keep pretending that you aren't. It's inefficient to have this conversation every time, do you not agree?' She nodded dumbly, blaming her failure to understand where this was heading on bumping her head. 'Therefore, I have a proposal.'

'A proposal?' She asked uneasily, scowling when he rolled his eyes impatiently.

'Yes, Molly. A proposal, suggestion, offer-'

'I know what it means,' she said fiercely.

'Good. Where was I?' She muttered 'proposal' dully, 'I suggest that we have an arrangement, for a… How do you put it? No strings attached relationship,' she raised an eyebrow, and he coughed uncertainly. 'I mean that if I'm bored, or if you're… well… whatever… Then we can find each other and…' She'd never heard so many pauses in her life, a wide smile creeping onto her face when it occurred to her that he was nervous.

'Shag?' She finished, biting her lip when he swallowed thickly, his curls falling softly over his face. 'All right,' she said suddenly, his eyes flying to hers.

'All right?'

'Yeah.' She stretched out her palm. 'Deal.' He shook her proffered hand, and she traced the lopsided grin that spilled onto his mouth.

'Deal.'

xxxxxx

The hospital wing was cold as she sat in the chair beside his bed, her only source of warmth the hand that held tightly onto her own.

The sun had set hours ago, but she had refused to leave his side, with a firm grip on the frame to ward off anyone who would dare to remove her by force.

Now, in the darkness, she could only picture Jim's face as he fell.

The spell had impacted in the centre of his chest, the light absorbed right over the spot where his heart should have been. The Stunning Spell that she hadn't made the conscious decision to use had frozen his expression, and his eyes still contained the rage that had formed when Sherlock had said her name.

Sherlock.

Molly looked up at him, sleeping soundly, and she gave into the temptation of brushing away his hair from his forehead; her touch lingering as she reminded herself that he was safe.

But she snatched her hand away when his breathing hitched, watching in horror when his eyes flickered open, his eyelids heavy as he noticed her perched beside him.

'Molly,' he said her name so softly, and she rested her palm on his cheek in response when she realised that the lump in her throat had stolen her ability to speak.

It was the first word he'd uttered since she'd helped him out of the meeting room, whispering 'Mycroft' to her as she locked Jim inside. He'd been so weak that she'd all but carried him to Professor Holmes' office, and he'd been brought immediately to Madam Pomfrey once Molly had finished explaining what had happened to him.

'You're here.' His voice was raspy, so she passed him the glass of water on the bedside table, waiting until he had finished before she replied.

'Your brother let me stay,' she said quietly.

'Mycroft has his moments,' Sherlock murmured thoughtfully, and they were silent again, Molly nervously picking at a tiny bobble on the duvet.

A gentle tug on her arm brought her gaze back to him, and she blinked when she saw Sherlock edge over, too tired to protest when he began to shuffle the covers down.

Molly slipped off her ballet flats and crawled in beside him, melting into him as his arms encompassed her, tucking her head below his chin as she buried her face in his chest.

'I'm so sorry,' her voice was muffled against his jumper, tears seeping into the fabric as his hold on her tightened.

'Don't. It's not your fault,' he said firmly, and she wanted so badly to believe him.

'I should have stopped him,' the words were marred almost completely by her sobs, and he pressed kisses to her head, stroking her hair until she quieted.

'You did. I wouldn't be here if you hadn't.' Her throat caught at that, fisting her hand in his jumper reflexively. 'It was my fault for pushing you away.'

'Why did you?' She felt his mouth open, but it was a long time before he said anything.

'I didn't want to put you in a position where you would have to choose.' She froze. 'I was afraid that you would pick him,' his voice dropped as he finished, but she heard him, drawing away to find that he'd shut his eyes tightly.

'You,' she said instantly, waiting until she could see blue again before she pressed her lips to his. 'I pick you, Sherlock. I'll always pick you.'

He kissed her deeply at that, pulling her closer until there was no space between their bodies, a mess of lips and limbs wrapped under the covers.

Her brain began to slow from his closeness, and she embraced the tranquility: finding a kind of quiet passion in the way his thumb traced her jaw line, different to the frantic encounters they'd had before, but so welcome now that she allowed herself to need him, rather than simply want him.

xxxxxx

Madam Pomfrey found them in the morning, nestled together inextricably, and presumably both fast asleep, even though Miss Hooper was so buried in Mr Holmes that the matron couldn't quite tell.

She shook her head in despair, but she still didn't have the heart to wake them, allowing herself to soften for a moment when she remembered how exhausted the girl had been the night before.

She looked at the watch on her wrist, musing that she didn't absolutely need to wake them for at least another hour, when Professor Holmes had promised to come and visit his brother.

She nodded primly, deciding that she would finish the stack of paperwork in her office until that time as she turned away from the bed.

But she stopped to pull the curtain around the sleeping teenagers, and there was a ghost of a smile on her face as she did so, a voice inside her head reminding her that sometimes the simplest medicines were enough.

A/N: Thank you BrytteMystere for the awesome prompt, I got very carried away with this! I also wanted to say that I imagine Madam Pomfrey as a young woman in this, and some strange part of me thinks it important to inform you of this. Don't ask me why.

I hope you enjoyed it, and to those who are kind enough to read The Bridesmaid and The Groom, I hope to have another chapter of that up soon.

*SHAMELESS PLUGGING* If you have any other prompts then let me know, either in the comments or on my Tumblr (AquaFontem). I'll usually use the tag 'AFWrites' because I am incredibly unoriginal, so you can check that out if you're interested… :)

Anyway, thank you so much for reading, and I hope that you're having an awesome day. :-)

P.S. The title is taken from the song by London Grammar, purely because I like it and listen to it all the time.