The first time Severus used a truly dark curse he expected it to fizzle up his blood like an electric shock, to burn his skin and the inside of his skull and leave scars behind, skewered and ugly marks he would never be free of.

Instead it was easy, it was so easy in the first second he'd thought it hadn't even worked, that he did something wrong and the magic leaking from his wand wouldn't do what he had intended.

But then the rat began to shriek. Twisting and squeaking, its small paws grasping at nothing and its tail lashing helplessly. And the boys – vultures, snakes, pale eyes in the darkness, laughing mouths and sharp teeth – had cheered, had clapped him on the shoulder or back, maybe too hard but it was warmth of human contact nonetheless.

And Black had been among them, his eyes as clear and unreadable as always and Severus had hated him and hated himself and hated the harpy and Dumbledore, who had forced him into this position in the first place.

Why had it all been so easy? Severus thought it would be difficult to rise in the ranks, to earn some smidgen of respect where before all he had to contend himself with were ambushes and verbal put-downs, starving and showering in the middle of the night so he wouldn't have to turn his naked back on anyone, so he wouldn't be too far from the protection of his wand, stuffed underneath his pillow while he slept fitfully every night, startling awake at the smallest sounds.

But it'd been easy. Just as easy as the unforgivable curse, and why hadn't there been more resistance when he attempted it, why hadn't something in his mind or his magic or his body protested before the spell left his lips? Had he been born for this, just as the stupid hat had assumed all those years ago, was this what he was meant for?

Or was it simply because what should stop wizards from using those curses was not the magic itself but their own heart and determination?

If so, Severus had already lost.

He had lost from the moment he had first approached Mulciber and Avery, the bottomfeeder Slytherins who weren't consigned to that position because of their birth but because of their incompetence, better blood but inferior intellect, forever banished to the fringes of their elite circle, a mob that was useful for mindless cruelty and jeering but not much else.

Severus didn't stay with them long. No matter his muddied heritage, he was too valuable, one of Slughorn's most favoured pupils and able to brew potions far above their curriculum not to mention his spell experimentation, so he rose in the ranks, suddenly sitting next to Rosier or the Carrows – and finally Black.

But the demands made of him rose alongside his status. Instead of spewing flattering words and assurances, he was taken along to secret midnight meetings, instead of simply listening to them brag about all the dark spells they had mastered, he was forced to try them himself.

And then there was no going back. Severus was one of them. Instead of half-blood, bastard or other slurs he was suddenly addressed as Snape. And when they found out that Snape was the name of his disgusting, muggle parent some of them switched to Prince, his mother's maiden name, a good, pure, wizard name that he should be claiming as his own, now that he had some value.

From Half-blood to Prince. How worthless, how easy – how ridiculous that something like elation rushed through him whenever someone called 'Prince' after him. When instead of starving, they pushed the roasts and mashed potatoes closer to him, no promises of beating them up his throat again should his dirty hands touch them.

And then his appetite vanished. Where before saliva had been pooling in his mouth, where he had been so eager to take just one bite he was now nauseous, looking at all that food, looking at their grinning faces.

At least Black hadn't made it that easy for him. At least he didn't fall over himself to get Severus to do things for him, at least he still sneered and kept his distance. And though he was the reason Severus was even here in the first place, even though he was the only one Severus was actually supposed to get close to, it felt like a balm. A stinging, nettling balm that itched but helped in some strange, inexplicable way.

And Severus had never tried to become Black's friend. The label 'friend' in Severus' mind would always belong to only one person, as she was the only one who deserved it.

He just had to get close enough to Black so he could 'keep an eye on him', close enough that no one would wonder why he was hanging around him. And so he played the Half-blood Prince, shrugged it one like a disguise that sometimes fit a bit too well, when his snide remarks and scoffs were suddenly accepted and appreciated, when they looked up to him …

He let it stretch over his skin, over his eyes and his mouth and Black didn't scatter or grow suspicious, but he stayed aloof in his own little bubble, surrounded by his sycophants but not close to any of them.

And so Severus started following him. It wasn't hard, he'd learned to move unseen in this castle long ago, to avoid anyone coming across him when he didn't want to be found, when he needed some quiet and some shelter to lick his wounds in private. But Black had none of the awareness that had been beaten into Severus, those lessons that had started long before Hogwarts, and so he never noticed his long shadow, silent and swooping.

Black had a few strange hobbies. Sometimes he'd make his way up the astronomy tower and stare at the Quidditch pitch and Severus soon noticed that he only did it when Gryffindor was practising. But he never went close to their table in the Great Hall and never even put foot on the stairs that would lead to their common room. He liked reading but apparently wanted it to be a secret, so Severus found him more than once sneaking into the library after curfew. The books he picked were random, as far as Severus knew. Some were about history, some were about magic, big tomes locked away in the forbidden section Black had no problem defusing before opening, and then he sometimes picked at storybooks or fables, things wizards would read to their children.

And then he visited the kitchen, a fact Severus only found out after he tickled the pear on that portrait himself and sneaked into the room once Black was back in bed. Only to be confronted by a sea of big, blinking eyes.

Of course Severus knew about house elves. He knew what they were and what they were here for, but he had never seen so many before. And they might have freaked him out in the first second.

He just hadn't expected to come across anything alive in one of the spots Black haunted. Severus had always assumed the boy valued his solitude. But apparently house elves weren't included on the list of beings to avoid.

And then he somehow found himself with a warm cup of tea pressed into his numb hands, his long fingers curling around warm porcelain and his tired eyes watching the swirls of honey glisten underneath the steaming surface. And all the appetite that he'd been missing returned while one of the house elves – Blim, he'd introduced himself as Blim – patted a small stool in the corner of the room and told Severus that 'Master looks like he needs a rest'.

And Severus had needed it. He hadn't really spoken to the house elves, and they hadn't disturbed him in his corner, simply delivering a plate of cookies and another hot cup when it looked like his first was running out. He was allowed to just sit and loosen the mask on his face, to taste the overly sweet concoction that made his teeth ache and his stomach almost glow with warmth as it spread through him. For the first time in months Severus felt like himself again, like he was actually living and breathing in his own body and not some caricature of himself. In that moment he wasn't the Half-blood Prince, he was simply Severus, thin and exhausted and cleverer than most and born to a witch and a muggle who both hated the other.

And of course that was the moment when Black breezed back into the room, words freezing on his lips as soon as he spotted Severus.

"Prince? What in Merlin's name are you doing here?"

And Severus intended to say 'None of your business' or 'I could ask you the same' but instead what left his mouth was: "Don't fucking call me that."

He expected Black to scowl or to throw a curse at him or to ignore him. Instead he grinned. "'Fucking'? I remember your base tongue and lowly insults. Never seen Lucius look that constipated."

Severus just frowned.

Black tsked. "Don't remember? You told him to offer you an oral service, back in my first year. At the station."

All Severus remembered was waking up disoriented and cold in one of the corridors, his clothes sticking to his back with sweat and blood and the iron taste of it burning his throat.

"Well, it's better than you always going 'Merlin this' and 'Morganna that'. Has no one ever taught you how to curse?"

If someone had asked him the next night why he was in the kitchen, eating snacks prepared especially for him and teaching Regulus Black, toujours pure, scion of the wizarding aristocracy, stuck-up prick, the difference between 'fuck off' and 'fuck-up' he wouldn't have been able to explain it.

But it happened nonetheless. They found some strange kind of rhythm, as if the kitchen was a neutral zone on a battlefield, where Severus was allowed to be someone other than the perfect Slytherin half-blood and Regulus Black was allowed to curse and be a brat. And it worked.

That's of course when she appeared. Harpy, pain in his ass, the reason he was even bothering with all of this in the first place.

Petunia Evans. In the dungeons, his dungeons, the Slytherin dungeons and the last place she should ever go.

She stalked through the dim halls like a stork with her stupid long neck and thin legs and Severus could already see her wings ripped clean off, could see her screeching and spasming on the cold floor, her stormy eyes bugging and blood-shot and then empty, so empty …

He had to get her out of there and he didn't really care why she was suddenly asking about the kitchen's and he didn't think about why he had agreed to show her – until she stepped through the portrait behind him.

And then he wanted to take it all back, rewind time and make the last half an hour disappear. He should have just let her be, should have let her deal with the consequences of her own stupidity and ignorance.

So what if she had come across some of his new 'friends'? So what if he knew that they were eager to practise on something a bit bigger than a rat? So what if she, muggle through and through, would have been just perfect, would have screamed real pretty for them?

So what?

It was still better than her being here. And he knew that he had only dragged out the inevitable.

She wasn't any more safe in the kitchens. It was only a matter of time.

Do what you feel is right.

Petunia didn't know if what she was currently feeling should be classified as 'right'. Confused, yes. Overwhelmed, maybe. Uncomfortable, definitely.

"So, you're wearing these rags because … anything else would set you free?"

"The gift of clothing is the highest honour."

"So, an honour is something you want to have, right? Do you want clothes then?"

"Only if our master sees fit to bestow them."

"But freedom is something you wish for?"

"Only if our master wishes for it as well."

Petunia swallowed, beating the butter harder, glad to have an excuse to look away from too-big eyes and naked feet on the cold stone floor. The rhythmic rasp of her whisk scraping against the bowl filled the air, lulling a short stop in the conversation while Petunia tried to gather her thoughts.

"So, you get no money and no clothes for working here. What's in it for you?"

"It's what we are born for," Blim replied. The slim elf was the one Petunia had internally designated as their leader, usually the first one to greet her and the one to delegate tasks to the others.

Her gaze wandered to Pitts, who was as always half hiding behind one of the shelfs, still nervous in her presence. She didn't really have to wonder why when she thought about the scars criss-crossing his arms or the fact that he only had three fingers left to grasp at jars.

By now Petunia was familiar with most of the regular house elves inhabiting the kitchens – or at least the ones who showed themselves to her. There was Filk, curious and bold and even though her face was as wrinkled as the others, Petunia had a feeling she was quite young. Glimkey usually hung around her, quiet and with the biggest, saddest eyes Petunia had ever seen. There was Retch, who was loud and grumpy and hopelessly in love with Vekey, who was clueless but polite.

All of them were wearing those potato sacks, a Hogwarts emblem sewn neatly above their chest as if the fraying, grey cloth was actually some kind of respectable uniform. It only made them look even more shabby.

"Are you sure you don't need any assistance?" Blim asked. "I could make a cake for you – it would only take a moment."

He lifted his spindly fingers and Petunia had seen the gesture enough times by now to know that he really could do anything he wanted, without a wand or fancy incantations, simply with a snap of his fingers or a roll of his wrist.

Which begged the question why these powerful creatures – Petunia would bet, more powerful than the conceited wizards gorging themselves on their labour and throwing their dirty laundry their way – were confined here into these small hidden spaces. They should be the ones living in this magical castle, waving their hands to fulfil their own needs and wishes instead of being treated like useful vermin.

"Thanks, Blim, but I'll do it myself."

Petunia whisked the sugar into the butter, making sure they mixed well until her shoulder was smarting. The aroma of fat and sweetness teased her nose, the tense muscles in her neck slowly relaxing.

She had never baked a cake for Lily before. Even now she wasn't sure how she felt about it, if the nerves swirling inside her stomach were because of the house elf dilemma she couldn't stop thinking about or the fact that she was baking a stupid birthday cake for her little sister.

But whenever she had almost convinced herself that what she was doing was unnecessary and sentimental and that she was just opening herself up for hurt, she remembered Christmas. She remembered sitting in the kitchen with her mother, she remembered her resentment merging with pity and making her almost sick. And no matter what, Lily would always be her sister. What was one cake in comparison?

And a small, bitter part of her was almost eager for Lily to reject her, so Petunia had no more reason to care about her. Because no matter how often she tried to convince herself otherwise, she did. The whole Order of the Phoenix debacle had only driven that point home.

And hadn't Lily tried to help her with Aspen? Hadn't she sat down with Petunia and asked her friends what to do and listened to her story?

What was one cake …

"The eggs, Miss Petunia."

"Thanks." Petunia noticed Blim's ears twitch as he poured the already cracked eggs into her mixture. Looking at his face she guessed it must be a sign of happiness or embarrassment.

Probably, he hadn't been thanked a lot in his life.

"My utmost pleasure."

It was only as she tipped the finished cake batter into a form and put it in the oven that she allowed her thoughts to return to the matter at hand.

"Did you like the Quibbler I brought you?"

"Oh yes, I enjoyed it immensely. Thank you for lending it to us."

Petunia nodded, feeling like an elephant in a china store. Everything about this situation appeared so delicate and she wasn't sure how to proceed, where to step to not shatter everything. "So … I'm sure there are other things you enjoy. Why not ask for money for your work? Then you can buy whatever you like. And you're still helping the wizards."

Blim was already shaking his head. At least he didn't look offended. "Being a house elf means committing your life to service. There is no need for compensation."

"What if they offered it? Because they appreciate your service."

Blim looked confused for a moment. "But there is no need for them."

"Maybe some of them want to."

This seemed to stump him and Petunia gave Blim all the time he needed, focusing on the dough slowly rising in its baking form. It was a simple butter cake, not one of the Victorian sponge cakes Petunia knew Lily actually favoured.

"If it pleases the Masters … then it would be good."

Petunia blinked.

"If the Masters wish to reward us and are happy to be doing it, then it would make us happy as well. We'd not be neglecting our duties."

Petunia hummed her agreement, forcing her eyes to remain on the unfinished cake, not wanting to pressure Blim. His voice sounded less sure than usual.

"Well, I'll get back to the dishes," Blim said, dusting his hands. "Enough dilly-dallying and theoretical nonsense, there's a feast to prepare. If you need me, just call. That oven can be temperamental."

Petunia sat in the kitchen, allowing the sound of bustling activity around her to lull her thoughts until they were less frantic. The sweet, warm scent of baking enveloped her and she felt unusually calm.

She still wasn't sure if this was right. If this feeling currently spreading through her like dye soaking a blank page could be described as that elusive concept she failed to grasp.

But she knew that she felt better. And that was all she could really ask for.

The cake was a towering monstrosity consisting of heaps of glittering cream, pink fondant, sugar hearts and twinkling candles.

Petunia almost expected it to burst into multicoloured sparks as part of some kind of mirage, a wizard trick, but it remained upright and solid, defying all laws of gravity and decency. She got cavities just looking at it.

But all she could think to say was: "I thought you don't like pink."

Lily huffed, playfully put-out. "I don't, which is why Dorcas ordered it. And pink just so happens to be Madam Puddifoot's specialty."

"Ah." Petunia suddenly wished that she had thought to hide her own little cake until she had made sure it was actually needed. It now sat next to the heart-sprinkled multi-story sugar complex, quite literally overshadowed and looking even smaller, more unsightly and boring than ever before.

"Don't worry, it's edible." Lily paused. "I think."

"Lily! Come blow out your candles," the girl with the thick eyeliner called and Lily grinned and lifted her brows. She looked carefree and happy and so genuinely beautiful, her eyes sparkling and her cheeks dimpling, that Petunia had to look away. Her gaze ghosted over the tapestries hiding the walls, thick and dominantly scarlet with unicorns and lions stitched among mediaeval depictions of plants and birds. Their smell saturated the air, something musty and comforting, like dust warmed by the sun for hours.

It was the first time Petunia had been in the Gryffindor dormitory. The few evenings they saw each other, Lily went to visit Petunia in her chambers, chuckling at Fluffy and not really saying anything despite talking until her curfew forced her to go. Now it was Petunia invading her space, and she had no doubt about the fact that this was Lily's space, more home to her little sister than the room they shared back in Cokeworth, with the way she moved through the crowd of well-wishers, her feet never stumbling over the edge of a carpet and her shoulders turning just right so she wouldn't bump against one of the curtained beds.

Lily made a show of blowing out the candles, huffing her chest and inflating her cheeks until they turned apple-red but no matter how hard she tried, they always reignited after a few seconds. In the end, among a chorus of laughter, she swung her wand and muttered some spell and then they all flickered out, the smoke curling towards the ceiling smelling like roses and puffing just as pink as the frosting. There was a smattering of applause and teasing and Petunia quickly clapped her hands a few times, not wanting to stand out any more than she already did.

She was decidedly foreign amongst Lily's friends, and it wasn't only the magic that separated them. They all looked so young despite Petunia only being a year or two older, and at the same time so self-assured, as if they knew something she didn't. They wore robes or pretty clothes that stirred in an invisible breeze, their faces fresh, all pimples and small flaws wished away and they were loud without being boisterous, cheerful without being forced, self-confident without being conceited.

They saw Petunia. Of course they did, despite sometimes wishing otherwise Petunia had yet to turn invisible. She noticed them noticing her, the odd one out, the one no-one really knew what to do with, but they mostly left her alone. A few had approached her, the girl with the wild, untamed curls she was wearing proudly and the one with the lipstick that was so deeply red Petunia thought it looked indecent, but those encounters had quickly tapered out after a few exclamations of 'Ah! You're the sister, right?' and 'Lily talks about you a lot' which felt a bit hard to believe.

But her solitude couldn't last forever.

"Did you make this?" It was a girl with eyes so big Petunia almost thought they should drip from her face, chipmunk cheeks and a soft smile, holding a piece of her butter cake. "It's delicious."

"Oh." It took Petunia a few seconds to process the compliment for what it was. "Thank you."

Shrieking laughter directed their attention back to Lily and her huddle of friends. They were busy opening presents and something especially interesting must have happened, judging by the excitement. Petunia could hear someone say 'That one's from Potter, I'm betting all my gobstones' and she almost made a face at that name.

The girl next to her didn't share her sentiment, instead sighing wistfully.

"It's nice to have moments like this. Lately, everything can seem so grim."

Petunia's brain needed a second, to switch from vengeful fantasies of pushing Potter and his smarmy smile down a flight of stairs to the much heavier topic the girl was breaching.

The ever-present war. It had been a long time since Petunia had allowed herself to linger on the thought and she was suddenly held in a tight grip of unwillingness. Why did this girl not simply ask how Lily had celebrated her birthday when she had thought she was 'just a muggle' like the other girls had?

"It helps to know we're doing something, however small."

Petunia froze. "Doing something?"

"Yes, you know …" The girl waved a hand as if it was self-explotionary. "For Dumbledore."

Petunia thought of cryptic words and winking sky-blue eyes. "The headmaster?"

"Once a teacher, always a teacher." The girl took another bite, yellow crumbs clinging to her lips. "He likes helping us out – I don't know where we'd be without him."

"He teaches?"

"More like an extracurricular." And the girl looked at Petunia before smiling and something about it rubbed her wrong. It looked too secretive, it looked too much like there was an undercurrent hiding beneath that placid expression, about to rip her feet out from under her.

Petunia's mouth moved without her conscious thought. "An extracurricular? Like a club?"

The smile deepened and Petunia felt sick. She knew what was coming before the girl even spoke.

"More like an Order."

And suddenly there was so much red around, the whole room was red, from the bed sheets and pillowcases to the curtains, to the wall drapings, to the little hearts stuck to Lily's cake. So much red, so much rage, so much blood and fire and Petunia was standing right in the middle and she could feel herself burning.

She almost expected flaming feathers to rain down around her.

The next moments happened almost in a trance. She heard herself apologise to the girl, claiming she had to talk to Lily about something important, she saw her hand clamp around Lily's upper arm, her fingers bony and curled like claws, she saw Lily's startled and confused face while Petunia tugged her outside.

And then she was walking, walking and ignoring Lily's increasingly annoyed demands to know what was going on, because how could she, how could Lily – Petunia thought that this matter was over, she had paid her dues in Lily's tears and silences and the contempt she had endured, why had it been all for nothing, why was it once again …

"The Order of the Phoenix?"

Lily paled. She stopped moving and Petunia followed suit, letting go of Lily's pinched skin and ignoring the red (red, red, red) marks she had left behind. There was a window next to them, presenting a view of sprawling hills and a glittering lake, so much green and blue that it allowed Petunia to breathe again.

"Lily, you promised."

And with just those few words Lily's eyes hardened into shards of bottled glass, not yet smoothed by the sea, ready to cut. "Just leave it, Petunia."
"You promised," Petunia repeated and she was strangely detached, her voice not hoarse or brittle, there were no tears trembling on her lashes or quivers chasing her chin. She could feel them, but they were suppressed under a blanket of snow, leaving her expression frozen and her tone cold.

"Well, I promised them as well. I promised I would help, that I would do my best to save people. So I guess I'd be breaking my word either way and I'd rather prefer the one that lets me sleep at night."

"What about Mum?"

"Are you going to tattle again?" Lily laughed, but it was strange, it sounded wrong. It wasn't light and filled with merriment, no tinkling of bells. "Why do you always have to do this, why do you have to play yourself up as some kind of saint and then judge me? And why do we have to do this now, on my birthday, with all my friends wondering where I've gone?"

And something twisted in Petunia's throat, something hot and spiky and she didn't know if she wanted to laugh or cry.

You're a child, she wanted to tell Lily. Here her little sister was, caring about her birthday and not making a bad impression on her school friends and in the same breath she talked about joining an organisation to go to war against people who were murdering and torturing and doing things Petunia couldn't even imagine.

"Don't, Lily."

"Don't what? Don't help others? Don't make use of the gift I have to make sure no-one has to suffer? Don't stand up for all I represent, all my birth and my blood mean in this society?" Lily stepped away, as if she couldn't physically stand being close to Petunia. "You want me to cower and flinch while others fight my battles for me? You want me to look away? Just because it's not about you, doesn't mean it isn't about me. Just because you have no trouble ignoring everything that's happening, just because you are happy to hide behind your ignorance, doesn't mean I am!"

Something in Petunia's chest thumped hollow. It didn't hurt, it didn't burn or sting in any way, it just felt like a big hand had scooped something out of her and left an empty space behind, one she could hear echoing and but not feel bleeding.

Lily blew out a long breath. She tugged at the end of one of her pretty braids. Petunia wondered which of her friends had done her hair for her.

"Just don't try to make my decision for me, Tuney." Lily looked at her, her face too calm. Petunia knew, with the instinct of an older sister, that she was still angry beneath it. "That's all I'm asking. I don't expect you to cheer for me or understand why I'm doing this. Just … don't make it harder for me than it already is."

If she was waiting for an answer, Lily would be disappointed. Petunia thought that all her words had been nestled in the space that was now empty.

"I'm going back to the party," Lily finally said when the silence turned from uncomfortable to unbearable. "You're welcome to come along."

But Petunia thought neither of them was surprised when she remained behind. Lily's back grew smaller and then she disappeared around a corner and somehow it felt like Petunia would be unable to find her even if she ran after her right this second.