Tonight is the night.

They're both sitting at their bedroom windows, waiting for the owl that will finally settle, once and for all, which of them is the undisputed queen of the school. Oh, they've been going back and forth at each other for six years now, both of them making their House Quidditch teams at absurdly early ages and taking great delight in showing one another up on the pitch, both of them making Captain, both of them making Prefect (one of them by the skin of her teeth, and, she strongly suspects, more as a punishment than an honor). The last six years at Hogwarts, since Regina Mills and Emma Swan strode up the steps to the Great Hall and managed to trip one another on the way to the Sorting Hat, have been a dogfight. But tonight ends all that. Tonight they'll know who wins, once and for all. There can, after all, only be one Head Girl.

Regina is sitting, hands folded in her lap, on her wide, cushioned window ledge, drapes and cushions done up in silver and green of course, as is only befitting the Slytherin Prefect and, she's sure, Head Girl. She jumps a bit when she hears a knock at the door and it creaks open, revealing Mother, whose knocks are only for show. She'll be coming in whether she's wanted or not.

At this moment she's not particularly wanted. If Cora Mills were the sort of mother to dole out comforting words and hugs, and if she had raised the sort of daughter who expected or accepted them, Regina might welcome her presence. But neither of these things are the case. Cora's eyes rove over her daughter's silk pajama-clad form, the tight braid she's captured her hair in, and she lets out a little sniff. Regina straightens her already ramrod-straight posture.

"Darling, you're up awfully late, and you know we must be going to Diagon Alley tomorrow for your books. What is it that's keeping you from your bed? Something making you nervous?"

Cora knows exactly what Regina's waiting for, but she wants to see how her daughter will react. Regina knows that only one thing is certain with her mother: everything's a test. She gives Cora a cool, practiced smile. "Nothing, Mother. Just excited for tomorrow."

Mother raises an eyebrow but chooses not to pursue it further. "Very well, darling, but not too much longer. I want to get an early start so we can be done before the shops get too busy. Goodnight, dearest."

Regina watches her go with a sigh. Of course it won't do to have Cora Mills and her daughter mingling among the rabble. There might be Muggleborns among them for Merlin's sake. Never mind that Cora Mills is Muggleborn herself – her mother won't let that secret out for blood or money, and Regina is fairly sure Cora has spilled both to keep the secret safe. Officially Cora comes from relatively muddy heritage, some exotic wizarding family from Spain or Sicily or Brazil – something like that. The story seems to change every time Regina hears it. But all that matters is that she married Regina's father, the scion of a prominent (if penniless) Pureblood family which Cora's ruthless business acumen returned to affluence well before Regina's birth, and that makes Regina Pureblood through and through. If only it were that simple.

Regina returns her gaze to the window, the placidity of her expression unreflective of her inner turmoil. Her father used to take her out riding on one of his Abraxans, and they'd go out until nearly midnight, looking at the stars. He'd attempted to teach her the names of the constellations but she'd not been interested, and they'd spent many an hour making up silly names for imagined star groups instead. The Whinging Witch… The Guilty Gryphon… The Tremendous Toad… Such things had left her life when her father passed away, the summer before Regina first went to Hogwarts. She'd been in shock, a grieving, disoriented little First Year who had gone from casting minor enchantments at the age of eight to hardly being able to throw a spark, so dense was her sorrow. Perfect internal weather for a lifelong vendetta, and that was where Emma Swan had come in.

Brash, loud, lionhearted, lion-maned Emma Swan, who'd tripped Regina in her haste to get into the Great Hall first. From the floor Regina had spat out a perfect Leg-locker Curse, making Swan fall flat on her face in front of the entire school and vow eternal vengeance. That had been the start of it; the ways they had fought each other and set each other up to fall and just generally needled each other had been many and varied. Regina finds herself thinking of Swan with a kind of wistfulness, tempered by a bit of a flutter in her tummy: the owl that will surely arrive any minute now will put an end to their endless rivalry, as the girl will surely be so defeated she won't even bother trying anymore. And if she does…well, Regina can remove up to forty points from Gryffindor in one go.

There – one of the stars has detached itself from the sky and is moving, getting closer and closer to her window. Regina clenches her fists tightly. This is it! The culmination of everything she's been working for – and Mother will be so proud – and if all goes well, it'll be Killian as Head Boy, and Slytherin will reign at Hogwarts forever and forever amen – at least until they graduate.

The owl, a snowy, drops to her windowsill and holds out the letter, haughtily staring down its beak at her with an expression that reminds her altogether too much of Mother. She takes the letter and thanks it, offering it a dead mouse that her own owl, Rocinante, killed a few hours earlier. It declines with a muted hoot. Then it's off again into the night, and Regina shuts her window and sinks back into the seat to open the letter with shaking hands.

Dear Miss Mills,

Congratulations. You have been chosen as Head Girl of this year's class at Hogwarts School of Witchcraft and Wizardry.

She doesn't need to read any further. She throws the letter into the air and pumps her fist silently, a display she would never allow herself if Mother were present but Mother isn't, so she lets herself loose just a little. Then she throws herself into bed, her mind racing with how Kathryn and Sydney and Killian will react when she shares the news tomorrow, but most of all that dreadful Emma Swan. At last, at long last, Regina Mills has had her revenge.

Across the country, Emma Swan is pacing her living room, fists clenching and unclenching. She feels like she often does before an important Quidditch match: riled up, anxious, and more than anything excited to win and rub it in Regina Mills's perfect face. There is a part of Emma that's still a child, small and scrappy for her age, picked on at the outset but more than ready to get into it with anyone who crosses her. And Regina Mills has crossed her, oh, more times than she can count. Ever since she embarrassed Emma in front of the entire school – she'd been known as That Girl Who Tripped for at least two weeks, before her classmates moved on to something else – Regina Mills has been a thorn in her side. They can't seem to stop clashing: in class, on the Quidditch pitch, in the halls, at inter-House parties, and, now, over this pinnacle of achievement for which Emma's still not quite clear on why she's in the running: Head Girlship over the entire school.

Emma's always had trouble paying attention in class; she's often gotten into fights, being blessed (or cursed) with an overdeveloped sense of justice; she's gotten high marks on exams but often forgets her homework until the last minute and winds up fudging it. But something about Regina Mills focuses her, makes her want to do better – no, best – and she finds herself trying harder than she ever has in her entire life just to make the girl's dark eyes flash, or her lip curl up with that sexy scar on it –

Emma pauses in her pacing to groan. And then that started – sometime around fifth year, she noticed that Mills had gotten disturbingly pretty. More than one midair collision, when the Slytherin Chaser has gotten too close to her goalposts, has ended in a confusing entanglement that leaves Emma's head reeling. But luckily for Emma's grades and academic and personal achievement, she hates Regina more than she lusts after her. Although Emma's still not sure how she made Prefect. When Headmistress Ghorm had announced her as the Gryffindor Prefect in their fifth year, Emma's jaw had just about hit the floor. Everyone had been expecting it to be Graham.

Eventually she had drummed up the courage to go the Headmistress and ask about it outright. Ghorm had explained – in the most pedantic way, of course – that she believed Emma had the potential for greatness inside of her. Given the responsibility, the Headmistress expected her to rise to the challenge. Half of Emma wanted to rebel against the pedantry, but the other half admitted that was something she wanted – if only to see the look on Regina's face when she excelled.

But all of that ends today. Today she triumphs, saves Hogwarts from the tyranny of the Evil Queen (as Ruby started calling her during third year, and the name stuck), and proves her superiority once and for all. There's a large part of her that can't wait to see Mills's face tomorrow when they go to London, can't wait to gloat – which of course her mother has to ruin.

"Now honey, I know it's exciting for you, but you have to promise me you're not going to lord it over Regina Mills if you get it," Mary Margaret says, watching her daughter pace. At her words, Emma whirls on her mother.

"Aw, come on, Mom, that's half the fun!"

"Emma, one thing we always say in Hufflepuff is that you need to learn to be gracious both in victory and defeat."

Emma looks away from her mother, jaw working over the words Well it's a good thing I'm not in Hufflepuff then. Even now, on the eve of Emma's seventh year at Hogwarts, it's still a sore point between them that she was sorted into Gryffindor and not Hufflepuff. Mary Margaret is a Hufflepuff through and through – so much so that she tried to decorate their house in Hufflepuff colors and Emma's father, not exactly the pinnacle of taste himself but at least more sensible than his wife, had to dissuade her. Black and canary yellow looked good on the banners draped conspicuously over the bannisters, on the walls, and in the kitchen. Hufflepuff colors wouldn't have looked good as curtains or wallpaper.

Even now, having been Gryffindor Prefect and Gryffindor Quidditch captain and having won the House Cup almost singlehandedly for Gryffindor during her sixth year (though she almost lost it singlehandedly for Gryffindor that year as well, but that's a different story), she worries that her mother, for all of her appreciation of Emma's achievements, can only look at her and think that all of those trophies and commendations and awards for Special Service to the School would have looked so much better in black and yellow. She worries at her lip as she looks at Mary Margaret, who looks away first.

Emma's father, David, manages to catch her eye and give her a big grin. He's a Muggle – he has no House loyalty, and she knows he loves her in whatever colors she wears. But that sometimes makes her feel disconnected from him: he doesn't understand the rivalry, the pageantry, the burning desire to achieve for one's mates and bring honor to one's House. It's simple with David in the places where it's difficult with her mother, but there's disconnect as well. She wishes there weren't, but she doesn't know how to prevent it.

Mary Margaret's voice, overly cheerful to compensate for the sudden lull, pulls Emma out of her brooding. "Now remember, we need to get to Diagon Alley extra early tomorrow so we can pick up Henry. He needs so much stuff – robes, books, and of course his wand…"

Emma grins at the mention of her cousin. Henry Swan is somewhat the family's collective little brother – his parents gone, he's been passed around the extended Swan family for two or three years at a time. He stayed with Emma briefly when she had just started school, and she remembers the little boy who idolized her, watching with gigantic eyes as she tentatively floated toothpicks and toadstools. He's about to start his first year, so he's come a long way from that little boy, but she's looking forward to him coming home with them. He'll be staying with them for the duration of his time at Hogwarts, as Emma's home is closest to the school.

"Yeah! And I can't wait to show him around, and introduce him to Graham and Ruby and Tink, and I'm gonna totally teach him Quidditch on the sly and get him on the team the second he's allowed to play, and he'll think it's so cool that his cousin's Head Girl…"

"Now hold on a sec, honey," David laughs. "You haven't gotten it yet."

As if on cue, a disgruntled hoot punctures the relative tranquility of the room. Emma's at the window in one long, ungainly stride – eliciting a gasp of concern from Mary Margaret, who keeps her glass unicorn collection far too close to that window – and snatches the letter from the owl's beak. It tries to snap at her fingers but she dodges it like a Bludger and rips the letter open.

Dear Miss Swan,

Congratulations. You have been chosen as Head Girl of this year's class at Hogwarts School of Witchcraft and Wizardry.

Emma pumps her fist in the air and crows like a cockatrice. "Hell yes! Mills is gonna die!" And for all that her father can lecture her on language and her mother can lecture her about good form, nothing can puncture the bright swelling bubble of victory in Emma's chest.

The morning dawns bright and cold, but it's still summer, so Emma ignores her mother's warnings to bundle up, knowing it'll get hot later. She's still buzzing on the events of last night and she can't wait to find Graham and Ruby and Tina – whom they usually call Tink, for some reason she can't recall, but it probably had something to do with too much Butterbeer – and tell them the news. She barely slept, but she's up at crack of dawn like it's Christmas morning and she's hustling her parents into the fireplace with a haphazard dash of Floo powder before they're even really awake.

It's close enough to the beginning of school that even this early in the morning Diagon Alley is packed. Emma could hardly care less about the list of books to be purchased and the new dress robes her parents have promised her in light of her success – she's immediately on the lookout for her friends, but also for one Regina Mills. She definitely wants to see the Slytherin princess before her enemy sees her. The girl did an independent study with Professor Gold on poisons last year, for Merlin's sake – she wouldn't put it past her to have something dastardly whipped up just for her.

But Emma's not exactly the sneaky type, so of course it happens against her wishes. At the first sharp report of that low, husky, certainly-not-sexy-c'mon-what-are-you-thinking-Swan voice, she whips around like she's been lassoed. "Miss Swan."

"Mills," she says cheerily, even as her hand goes to the wand in her back pocket. Her first thought, however, is that the look on Regina's face isn't the correct one. Those eyes Emma certainly hasn't spent any time at all thinking about should be snapping black fire at her, and her mouth shouldn't be curled up in the sneer that Emma most certainly hasn't named her Triumph Sneer – it should be the Fury Sneer, or the Swan You're Going Down (Maybe On Me) Sneer. Nope! Emma tells herself. No wrong lusty feelings. Wrong lusty feelings, go away. This is your moment of triumph here, Swan. Savor it.

"Sorry to hear the news," she drawls, pulling her letter oh-so-slowly out of her pocket. "Or wait, actually not that sorry at all."

"Yes, I'm sure your parents must be quite disappointed," Mills says, matching her drawl for drawl. All at once it seems to click, and they frown at one another. Regina pulls a matching letter from the pocket of her vest (why does she always look like she's going to go riding, Emma wonders, and why does it have to be so distractingly hot?) and dangles it in front of her, letting it unfold. Emma has to squint, but she can make out the first word: Congratulations

Her mouth is suddenly dry. "What? No, that's – that can't be –" And now she's fumbling for her own letter, nearly tearing it in her haste to make certain that it contains what she knows it contains, that Regina Mills somehow hasn't managed to work the black magic to make the letters rearrange themselves. But excepting the surname after the Dear Miss, the letters are identical.

Emma and Regina look up from their letters at exactly the same time, their gazes meeting and catching like flames. "What," Mills spits out flatly, her words like venom, "is going on?"

Emma can only clench her jaw and shake her head. "Honestly, I have no idea."