Full Summary: Severus Snape, Seventeen year old Slytherin, had his life mapped out to the finest detail. Then she came. Poppy Potter, sixteen and wayward, in a last ditch effort to win the war that had wrecked her world and seen many a good witch and wizard die, goes on one last mission into the past undercover as a Gaunt. Then she was placed next to a young Severus Snape in Potions. Merlin help them both.

Or: The A/B/O Severus/Fem!Harry fic no one wanted, that perhaps grew some legs while I wasn't looking, and got itself a little bit of plot. Not a lot, this is mostly pure, uncut smut, but there is some. If you squint.

Tags/Warnings: Female Harry Potter, Young Severus Snape, Alpha/Beta/Omega Dynamics, Omega Harry, Alpha Severus Snape, Scenting, Fluff and Smut, Alternate Universe, Mating Cycles/In Heat, Mating Bond, Mating Bites, Knotting, Masturbation, Literally In The First Chapter, It Really Is That Sort Of Fic, Shameless Smut, Time Travel, Slytherin Harry Potter, I have no idea where this is going, My First Smut, It might be absolutely terrible, Be Warned, Severus Snape Needs a Hug, Undercover Gaunt, Size Kink, Size Difference, Other Additional Tags to Be Added.

CHAPTER ONE:

Positively Fucked.

Severus Snape's P.O.V

Severus Snape was not stupid. Far from it. Distrustful? Yes. Condescending? Many would say so. Dry? Of course. Prejudiced? That too. However, stupid was never a label easily stuck to him, for all his faults and flaws.

And he had many.

He knew this.

Again, he was not stupid.

He was not a man easy to trust, and swifter to tell a lie if it got him what he wanted, even at seventeen. He was good at it too. Silver-tongued, they called him. Charming, in a droll way. Flattery gets you far in life, he learned, if you use it frugally. The right compliment to the right wife lead to her husband buying stocks in your business.

Or a demand for a duel, if you lay it on a bit too thickly.

Indeed, Severus Snape knew how to play people.

He had ambition in his blood, rich and hot, that saw him push through the disturbing shroud of poverty that blanketed him as a child. Growing up as he did, in third hand-me-downs, his stomach knotted in hunger from his father spending the last of their already slim purses on his gambling habit, with bruises for birthday presents and split lips for bedtime kisses, gave him a drive many of his contemporaries lacked. To never go back.

Only forward.

He knew exactly what he wanted, how to get it, and in truth, it did not really trouble him who he had to trample on to get there.

The world was a cold, cruel place, and only those with fangs survived.

For a Slytherin, he was a galleon a dozen.

For a man? Perhaps not so much.

For an Alpha, he was definitely not so typical.

He knew this too. He had the bulk, the height, that was characteristic of his designation. The aura that puts people on edge, yeah, he had that in the cauldrons. Yet, he was not handsome. Not in the way Lucius was. Or Dolohov or Rosier. Or, sweet Circe forbid, Potter.

There was an archetypal prowl to an Alpha. A great cat skulking. Snape lacked it. More bat than cat. There was no grace to his frame. No glossy finish. He was big, and a bit ungainly, still growing his mother argued, and when he walked into a room, all six-foot-three of him, people noticed in a not so nice way.

His ears were too big.

The same for his nose.

He was sullen, and surly, and sallow.

And he was perfectly fine with that.

For while he did not quite look like the typical Alpha, neither did he act like it. He did not swagger. He did not preen. He did not display his glands on his wrists or neck with strategically unbuttoned robes and rolled sleeves for the Betas or the sparse Omegas to drool at. To him, it was not a badge of honour.

It was something to overcome.

Severus Snape was more than his designation.

Perhaps it was because he did not fall into the traps most Alpha's do. He did not feel the heat, as Lucius described one night in their dormitory in third year, of being in an Omega's presence as Lucius did around Narcissa Black.

He did not make a right prat out of himself as Rodolphus Lestrange did, after smelling Bellatrix's, an Alpha, scent in the hall, where he went on to steal her robes from her trunk that night trying to roll and smother himself in the scent, before being caught by Filch of all people.

His glands never, not once, pulsed, as he saw Mulciber's do when he caught a whiff of Carrow on wind while they watched the Quidditch match between Slytherin and Hufflepuff.

Unlike his House brethren, he had never been in a rut, not one, where he had to be sent home or confined to the hospital wing until the dreaded week-long heat was over.

His mother simply told him he was a late bloomer, like her.

Severus thought there was something broken in him.

A lot of things broken in him.

He smelled them, certainly. His nose, as Lucius joked, was big enough to smell the whole Grand Hall in a single inhale, and he was born with fervently strong senses. There was no escaping that. He smelled the Betas and Alphas, and the few Omegas that swarmed Hogwarts halls. Beta's smelled bland. Eroded. Unobtrusive, but completely uninteresting. Alpha's naturally had an acidic bounce to their aroma. Sharp. Keen. Revoltingly unmistakable. Omega's-

Well, he only knew of three, given how rare they were.

Narcissa, Rodolphus, and Remus Lupin.

It was… Sweet. Sugary almost. Like fruit just on the wrong side of ripe. Nauseating.

And that was the problem, he found.

They were not meant to smell sickening.

Yet, they did to him.

Horribly syrupy and irritating to his delicate senses.

Like bleach mixed with sugar water and that cheap flowery perfume that second year nightmare, Umbridge, so adored dousing herself in to try and trick others into believing she was an Omega.

Now she was stupid.

He only remembered her name so he could sit as far away from the chit as possible at lunch and dinner.

Severus was okay with that.

Really.

He was not a typical Alpha. He was not, like his friends, transfixed with the ideas of mates and heat cycles and perfect balances. He had seen, first-hand, how horribly wrong Omega and Alpha bonds can go. His poor mother and his bastard of a father the perfect example.

Even Lily Evans, perhaps the one girl he had gotten closest to, the one scent he could halfway stand, before the whole 'mudblood' disaster last year, smelt… Alright. Clean, like fresh laundry, with the orange zest spring of an Alpha, pleasant but… Just that.

It was always just that.

Severus thought, accurately, that he had dodged the killing curse.

Without the heady cocktail of hormones and urges his designation was normally pumped full of, he had time to focus on the things that truly mattered. He became the best of his year, only falling behind Potter in Defence, Transfiguration and bloody Quidditch.

As if the latter was going to be actually important in the real world once they leave at the end of the year.

He became a protégée in Potions.

Slughorn was, this term, in talks with Dumbledore about taking him on in an apprenticeship after their final year.

From there, after his Mastery, Severus could do as he liked, far from the headache of Alphas, Betas and Omegas.

Perhaps open his own apothecary.

Perhaps work for the Potion department of Saint Mungo's.

Perhaps he would even start his own research.

Severus Snape had a plan, well-oiled and tightly rigged, and nothing was going to get in the way.

Only, something did get in the way.

She got in the way.

Threw a giant Omega shaped wrench into his machine and laughed as it sparked and fell apart right before his eyes.

Severus Snape was not stupid.

As soon as he smelled her, he knew he was fucked.

Metaphorically, absolutely.

He only prayed it was physically too.

Severus did not pay much attention to the welcoming feast. That was his first mistake of many. He knew Dumbledore's lines as he knew his Potions textbook: from cover to cover. If you had heard one welcoming feast, you had heard them all.

So, he zoned out.

His thoughts drifted to the last year Potions project he was undertaking.

Connecting dots, listing ingredients, tweaking the recipes he had mentally memorized.

Perhaps if he used pure aconite instead of essence, it would shave the brewing time down by at least fifteen minutes and then-

There was a murmur as the first years came doddering in, slight and jumpy, the odour of anxiety blistering in the air around them.

Nothing new.

The whispers, however, that stoked up from his table like flames of a bonfire were.

"Did Dumbledore say Durmstrang? I can see that black haired one coming from there, but the others? No way. Too clean if you catch my drift."

"Two Sickles on the brunette being Ravenclaw."

"Did you see that scar over her eye? What do you think caused that?"

"Bit odd, ain't it? Having transfers this late."

"Betas, the lot of them… Well, apart from the one with the scar. Look at that scowl. Alpha. She'd be pretty if she smiled more. Mother always says a lady should-"

Severus snapped up from glaring down at his empty plate, and scanned the small first-year crowd waiting to be sorted.

There was nothing to see, until you got to the back of the throng.

Four teenagers stood in black robes, unsorted. Giants in the small sea.

Well… Comparatively giants.

The brunette girl stood with her nose high, proud, more outrageous hair than anything else. The boy beside her was built like a beater, squat and square and painfully Beta. Ginger too, and, without much more than a sweeping glance, it was easy to see the Weasley in him.

The tallest of the quartet was a lithe fellow, brown haired, a bit… Twitchy.

And the smallest-

Snape could not get a good look at her. She stood with her back to them, facing her friends. He only knew she was small, barely up to his chest if they stood side by side, crowned in a black curl so dark it was almost blue underneath the candlelight. Which was strange for an Alpha. To be so small.

Tiny, really.

Her shoulders shook, and he thought she might be laughing at something the tawny haired fellow was blushing over.

He found himself leaning closer, if but to catch a waft of her voice.

He heard nothing over the din of the Grand Hall.

He could not scent them from their distance, either.

Even if he could, he didn't feel the need to.

Snape could piece together the murmurs, and the picture he saw was boring.

Transfers form Durmstrang, as odd as that was, coming to finish their final year.

Nothing more, nothing less.

He sat back and washed his hands of the entire thing.

It had nothing to do with him. As a Slytherin, you learned quickly when, how, and why to become involved.

Nevertheless, Snape found himself… Watching. Trying to catch a glimpse of the last in the quartet. A hint. A peek. And-

He shook his head.

Tired.

He was exhausted. He had stayed up all last night trying to finish going over his syllabus for this year. However, soon they were called one by one, mixed in with the first years.

"Hermione Dagworth-Granger!"

The brunette girl trooped up, unafraid.

"Ravenclaw!"

No surprise. He could practically see the uptight, bossy know-it-all already cooing about rules and regulations and what her books says, word for word.

Dolohov would get off on her, no doubt.

The next to go was Ronald Prewitt, not quite a Weasley as Snape had assumed, but not far off.

He joined, oddly, Hufflepuff, to gracious applause.

The other wizard, who in fact turned out to be some Longbottom, a Cousin Snape supposed, was promptly placed in Gryffindor.

Strange.

Very strange.

For friends, for they had to be for how they were amicably chatting moments prior, they couldn't be more different.

The last was only called towards the end.

"Poppy Gaunt!"

Lucius, who had been lounging beside him, arm slung over the back of his stiff-backed chair, stiffened. Snape didn't have the time to question the sudden shift in demeanour from his friend, who had been mocking the transfer students until that point.

He could only smell the shock cresting in his scent, salty.

Rinsed out by the trepidation that came flooding in, sour and tart like vinegar.

And then Snape saw her, for the first time, as she turned to take the seat on the podium.

Initially, he thought the name was wrong because, with those cheekbones and devil-may-care smile, she could only be a Potter. However, it was… Wrong. She didn't have the hazel eyes of the Potter family, but a startling green the shade of the decisive unforgivable. Too pale too. Flesh like milk in moonlight. Her features were too biting, angled a bit too severely, splendidly serpentine.

Her name suited her, Snape peculiarly thought, a bit gored, as if someone had come along and scooped out his insides and stitched in her.

Poppy.

Delicate but deathly. The flower of fallen soldiers and wars both won and lost.

Because that's what she looked like.

A fighter. A survivor. The scar on her forehead, peaking out between her onyx curls, was a gnarly thing. Dreadful, but graceful. A bolt of lightening tearing down her face in a flash of soft scar, touching down over the lid of her right eye.

The hat did not even touch her head.

"Slytherin!"

Lucius whistled low. He said something to Severus, he knew that, but, abruptly, he couldn't hear properly.

As if he was sinking.

Drowning.

Muddled and scrambled and-

She came striding to their table, passed him, towards the free seats at the far end, the only ones left, and-

Fucking hell.

He caught her scent, and that was his second mistake.

It wasn't sweet. There was no sugar or honey to find skulking there. It was crisp and cold, like snow fall on a mountain top, warmed with the electrical aroma that settled in the air just before a lightening storm. Neither did she have the distinctive flowery note Omegas carried. In its place was something… Dark.

There was nothing gentle to it.

It reminded Severus of black silk, slick and sleek, scaled in crystal.

He wanted to trample the snow and dirty it, stain it with the impression of his boot, of himself. He wanted to catch the lightening and feel it burn, scar him, singe his skin, and brand him. He wanted to snatch the scales and silk, squeeze so hard it shattered in his hands, embedded inside, right to his bones, and-

She met his eye as she passed.

He couldn't breathe, he couldn't think, he couldn't-

She breezed past.

Just like that.

A force of nature, there one moment, gone the next.

"Severus, are you listening? Severus-… Merlin, what has gotten into you! You're bleeding. The-"

He only snapped back into his body when he felt fingers grasping his wrist over his robe, tactically low, away from his pulsing glands thumping underneath his shirt cuffs.

Wrong.

It was the wrong fingers, not deft enough, thin enough and-

Lucius yanked his hand.

"Let go of the bloody goblet before you slice a finger off."

Severus glanced down.

The golden goblet was crumpled in his fist. Shattered and dented. The metal sliced into his palm, but he couldn't feel it. Not really. Only-

"Excuse me. I feel… Sick. I need… Pomphrey. I'm going to the hospital wing. I'll… I'll see you later."

The goblet clattered to the table. Lucius called his name. He heard none of it as he swept out the Grand Hall.

That was his third mistake, thinking this was something he could simply walk out his system.

All roads, like Rome, led back to her.

That night, in the sanctuary of his bed, muffliato strung up about him, hand salved and bandaged by a Pomphrey who chided him to be more careful, Severus did something he didn't do often.

He touched himself.

It was normal, he knew, as most teens did it.

Alphas even more so with their simmering libido.

Generally, however, he treated it like a business transaction. Playing his body with precise, swift motions to gain himself some relaxation so he could concentrate better. It was simple that way. Quick. Efficient.

There was none of that perfunctory and dutiful regard that night.

He just couldn't find it.

He could find her scent though.

Lodged in his brain, rooting in his system, wedged in his nose.

He couldn't shake it, no matter how many times he blew his nose or, against regulation, downed another suppressor Potion all Alphas took on the daily.

It was there, haunting him, tempting, calling-

He ached with it.

Scorched.

He tried to ignore it in the beginning.

Of course he did.

Severus Snape was more than his designation, and even his own body would not tell him what to do.

He's spiteful, that way.

Spiteful and aching.

He tossed and turned, and tossed all over again, tacky sheets sticking to his bare, flushed skin.

He felt heavy. Full with… Something. Something that had to give. Drain. Or he was sure, so bloody sure, he was going to burst.

Blood, spit or semen, something had to pop to ease the pressure.

By the weight of his cock as it twitched and strained between his legs, rigid as iron, his body had already chose for him.

Just this once… Just this once.

He reached down.

He hissed.

He felt hot.

Too hot.

Not nearly hot enough.

He thought of mountain caps, and silk rope, and the lightening came on its own. Piercing through him. He was leaking, he felt, seeping, wet and warm and dark, in his bed. He pumped, he twisted, and it was not enough.

It was never going to be enough to ease the burn.

The ache.

The want.

He didn't think, then.

He didn't have the capabilities too push through the haze that was choking him.

This was what desperation felt like.

Damp and deep and dangerous.

He was on his knees unexpectedly, ruffling through his bed, shirking sheet and seizing pillow. It was not enough. He needed more. A stiff fist and a winding wrist was not enough.

He rolled onto his stomach, over the pillow, fist back to where it was needed to be, frantically pumping, and he groaned.

Guttural.

Pained.

He sounded like a beast.

He felt like one too.

Feral.

Savage.

There was nothing slow.

It was fast and brutal and he couldn't stop.

His palm was wet.

His stomach was wet.

His forehead was wet.

Everything was slippery and sleek and stinging pleasantly.

All he could hear was the slap of his own hand, the pounding of his own heart, and the panting breaths he tried to catch but failed, and, Merlin, he could still smell that scent.

Green eyes on fire.

Flesh like milk.

Small. He'd dwarf her. Blanket.

She could take it. He knew she could. Fast, slow, wet, she'd take it and-

The knot stretched at his base.

A knot.

His first.

He was popping a knot and all he could do was thrust faster, squeeze harder, pump quicker. It was swelling, he could feel, growing impossibly big. Hot hurt that ached so fuckin' wonderfully as he squeezed. There was a pillow by his head, he shuffled, reached, squeezed, strained, bit and-

He was gone.

Severus raced, he rutted, still cumming, still going and it's all he could do but hold onto consciousness as tightly as he was holding onto himself.

He was there, but not really.

He was somewhere else. Somewhere fresh and crisp with silk and soot, and it was not his hand squeezing, but the clasp of a cunt, and he was knotted, locked between pale thighs, not a pillow, and there was not cotton between his teeth, but skin, skin that tasted of moonlight and copper and-

He came back to himself in a puddle of sweat, semen and a halo of feathers from his torn into pillow.

It was a mess.

He was a mess.

Trembling as he was, breathless and still aching, slowly coming down from the high he had gone careening over.

He sagged, boneless.

He could think again.

Feel again.

Most importantly, he bore anger.

Rage.

He hated her then, laying alone in a cooling puddle.

Detested her more than he had ever loathed anything, and he had not even heard her voice.

He could not even bring himself to think her name.

Just her.

An abstract shadow looming over him.

No.

That was it.

It was.

One fumble with his hand, and he was clean.

In the clear.

She would be nothing more than a blip on his senses, as Umbridge was, something to skirt around but overall forget existed.

That was his final mistake.

Thinking life would ever be so easy on him.

He had potions in the morning.

Slughorn placed her right next to him.

Fucked.

Severus Snape was positively fucked.

Thoughts?

A.N: This is, and will be, nothing but pretty much pure smut. I've never written smut before, I've skirted around it, but I really need some practice for my bigger fics that are, seemingly, heading that way to include it. So, what better way to practice than to just bloody write a dirty whole smut-fic by itself, lol? There will be some plot, I can't really help myself, but there won't be much, and most of it will enable smut to happen lol.

I also base a young Severus Snape in this fic on Adam Driver. Some people find that casting problematic, so do with it what you will. That's just who I picture.

So, enjoy! And please be kind, lol. This really is my first dive into this sort of thing, and I'm still learning the ins and outs of getting it right. If you enjoyed this, and I haven't somehow made you regurgitate your dinner in disgust, and you would like to see more, don't forget to drop a review, or I might pretend this whole fiasco never happened and go get myself dipped in holy water XD.