A Priori
By Isis_uf

Rating - M (violence, sex, cursing, adult themes and deaths)
Pairings - James/Lily (past James/OC), Sirius/OCs, Remus/OC, Peter/OC, Regulus/OCs, Hermione/?
Disclaimer - Mostly really not mine. Credit to JKR and several friends (see author's note at the end)
Summary - When Rodolphus Lestrange infiltrates the Department of Mysteries and travels through time to attempt to alter the course of history, it's up to Hermione to chase after him and stop Voldemort from rising to power in the past.


Prologue - What's Past is Prologue

The Temporal Anomaly Detector - or TAD as those who used the devices called them - had been pointing straight toward Potentially Problematic all day. The unsettling reading was an unwelcome sight to Hermione Granger who, at 19-years-old, had just become the youngest member of the Department of Mysteries' Historical Repair and Regulation Division ever to keep watch over the device. And when they said ever, they meant ever. Details like things not having happened yet didn't get in the way of their record-keeping. It was an exciting opportunity and Hermione knew there'd be a fair bit of stress in her job, but would it have been too much to hope for a solid day of Uncommonly Steady readings for her first unaccompanied day on the job? Apparently so.

With a furrowed brow and wary looks at the TAD, Hermione made her way through the bustling halls of the Ministry and into the much more sparsely populated office she'd been working at for the last few months. After the war ended, Hermione, Ron and Harry had all received many job offers from all over the world. Ron had quickly taken a position with the Chudley Cannons in their marketing department - a brilliant move by the marketing team to be sure, but possibly not quite the job Ron had expected. Harry was still weighing his options, but Hermione felt sure he would take a job with the aurors soon. Like Hermione, he thrived on being a part of something bigger, on making a difference. And while taking a bit of a break after the war was both well-deserved and a good idea, inaction didn't sit well with Harry for long.

For some reason, it had surprised virtually everyone when Hermione had taken her job at the Department of Mysteries. Ron in particular couldn't seem to figure out why she wouldn't just sit back and enjoy their success in the war. But after just a few months with no school, no battles to fight and no direction, Hermione had found herself listless and aimless. Her thirst for knowledge had left her interested in the Department of Mysteries and her Gryffindor love of adventure had driven her specifically to the Historical Regulation and Repair Division. They'd been more than happy to have her. After all, she already had experience with time travel.

"Granger," called a stout, plump woman with short spiky hair and a too-pointy chin. "You're late."

Hermione grinned widely at the brusque woman with a challenging gaze. This, Hermione had learned after several moments of panic on her first day, was a routine joke around the office. Time, after all, was completely relative around here.

"Surely your watch is wrong, Ms. Pertwee," Hermione replied confidently.

"Well one of them has got to be right," the woman replied, eyeing the seven watches adorning her left arm.

Everyone around the office was a bit strange, Hermione had realized shortly after starting there, but then she wasn't exactly average herself, was she?

"The Keeper wanted to see you when you got in," Ms. Pertwee told her, a bit more seriously.

In spite of herself, a sense of urgency settled over Hermione and she had to fight back the urge to ask her co-worker why she'd not told her this news straight away. If time was relative to Hermione's office, it was nearly irrelevant to The Keeper - or the only relevant thing to him, depending on how you looked at it. Paradoxes were commonplace with him, it seemed.

No one knew where The Keeper came from or how long he'd lived, if such concepts even applied to him. Hermione had only met The Keeper four times, but each time was unsettling in its own way. The Keeper existed in a space outside of time and as such had a unique perspective on it and a completely unique existence. The first time Hermione had met him, he'd been a man of about forty with ice-blue eyes, a thin face, wiry frame and hair graying about his temples. A few weeks later he'd appeared to have aged about a hundred years, with wispy white hair, poor eyesight, and abysmal hearing. She'd thought he'd not been long for the world, a notion that had given her co-workers quite the chuckle. The third time Hermione had met The Keeper, scarcely a week later, he'd been about the same age as her. It had thrown her, but nowhere near as much as it had the fourth time she'd met him when she and Ms. Pertwee had entered to find an irate toddler with icy eyes and a soiled nappy.

"Relax," Ms. Pertwee chided, rolling her eyes in exaggerated annoyance. "The Keeper thinks he's such hot stuff, but when you've been here as long as I have you'll start to learn that he's just an old man - no matter how old he looks - who loves riddles and lording over all of us like he's got the secrets of the universe dangling in front of us."

Hermione pursed her lips but said nothing. Ms. Pertwee might have a jaded view of her job and of The Keeper in general, but Hermione wasn't so sure that the man didn't have the secrets of the universe.

"Well, I suppose I'd best not keep him waiting," Hermione replied and Ms. Pertwee snorted in reply.

In direct contrast the the readings on her TAD, the office was slow and quiet - Ms. Pertwee headed off toward the 17th century filing room (Goblin Rebellion section); Dean Beckett, a fifty-something man with puffy cheeks and caterpillar-like eyebrows, was counting the grains of sand in a time-turner; And her boss, Sydney Bellisario, a willowy brunette who would have been stunningly pretty if not for her alarmingly large eyes, appeared to be resetting one of the many clocks in the office to run backwards.

"This is the most frequently I've known The Keeper to request us," Sydney said suddenly, and Hermione stopped mid-step at the weight of her boss' sudden gaze. "Since you've been here, I mean. I can't recall more than half a dozen times he requested us in all the years I've been with this office before your arrival. Why do you think that is?"

At a loss for an answer, Hermione fumbled a bit before finding her voice.

"Perhaps he likes my company," she proposed, somewhat ridiculously.

Her boss looked at her with overly-sympathetic eyes and pursed lips.

"It was a joke," Hermione clarified.

"Not a very good one, dear," Sydney clucked. "Just try to keep in mind that he doesn't understand us any better than we understand him. He means well - I genuinely believe that. I couldn't work here otherwise. But, in the grand scheme of things, when all of eternity exists for you simultaneously, a single person or even a single civilization would mean very little."

It occurred to Hermione that her boss needed to make some quality friends rather desperately. She couldn't imagine sharing such a sentiment.

"On that, we'll have to disagree," Hermione replied crisply. "There are people in my life that I can't imagine ever finding irrelevant, no matter how long I could live or how many people I might meet."

"There are times I forget how very young you are," Sydney replied, shaking her head. "You've been through so much and yet you still have such optimism, such faith in friendship and goodness."

Hermione smiled thinly back and tried not to be bothered by the belittling half-compliment. This woman was her boss after all. And, as had been said about The Keeper earlier, she meant well.

"If you'll excuse me, I need to um...," she said, gesturing toward the extremely ordinary oak door on the far side of the room that led to a space that existed entirely outside of time.

"Don't let me keep you," Sydney agreed, tacitly offering permission for Hermione to continue her work.

The Department of Mysteries - as Hermione had found out back in her fifth year at Hogwarts - was a never-ending maze of corridors and rooms that led to each other but ought not. Rather like an Escher painting, the Department of Mysteries itself was seemingly a contradiction, but made a strange kind of sense.

Perhaps appropriately, then, the door to The Keeper's office was entirely non-descript. There was nothing about it that might tell you it was potentially the most important door in the history of doors. It's only marking, in fact, was a small brass nameplate. "Marlon Tallis, Senior Manager of Temporal Regulation and Control," it read. Giving a man like The Keeper a title - or even a name, for that matter - seemed a bit presumptuous to Hermione, but The Keeper didn't seem to mind.

Opening the door and stepping through, out of reality as she knew it and into a sort of hyper-reality, Hermione found herself in the company of a fifty-something man she knew was the Keeper himself. He sat behind a desk, watching grains of sand trickle through an over-sized hourglass before tipping it upside-down.

"I was told you wanted to see me," Hermione said, more as a question than a statement.

"I do," The Keeper replied, looking up toward her. "Your presence is required to deal with a major distortion of the time stream."

"I... but I just checked the TAD and it was only on potentially problematic!" she cried with great alarm.

"And it is," The Keeper replied matter-of-factly. "In the time you checked it, anyhow."

Normally, Hermione found The Keeper's constant use of present tense and overall perspective utterly fascinating, but upon his revelation, she mostly just found it problematic to understanding what was going on.

"Absent his master Lord Voldemort, the Death Eater Rodolphus Lestrange infiltrates the ministry and gains access to the Department of Mysteries itself. He knows of our office and its function. In a move of sheer desperation, he bursts through these very doors and sends himself on a journey through history to rewrite it in his favor," The Keeper told her gravely, crossing his arms in front of him on the desk and staring over his reader glasses at her. "This cannot happen, of course."

"But, I was just in the office!" Hermione insisted. "Surely if a Death Eater had burst through our doors I'd have known about it!"

"I understand your confusion," The Keeper replied. "He enters immediately after the time you leave your world and enter mine. He steals some valuable artifacts that enable him - with very little control over his destinations - to jump through time three times."

"But..." Hermione protested, ignoring the problem of her own limited perspective on time and jumping straight to her most important questions. "My co-workers. My friends? What will happen to them?"

"I do not understand," The Keeper said, quirking his head slightly.

"If Rodolphus goes back in time and changes everything, what happens to my friends? Does Voldemort win?" Hermione asked desperately.

"My dear, your friends do not exist past the point where you walked through my door," The Keeper told her gently, much to Hermione's horror. "Lestrange's actions nullify your entire timeline. You are the only exception."

Light-headed and eyes brimming with tears, Hermione collapsed into the seat across The Keeper.

"I don't understand," she protested. "If this happens, why didn't you warn us? Why couldn't we stop him?"

"Because that's not what happens," The Keeper told her succinctly. "Time is not a line that can be altered mid-course, Hermione. Not on a grand scale. Not without dire consequences. Time exists. It is as simple and as complex as that. Just because you experience it in a linear fashion does not mean it exists that way."

Not one prone to tears, but somewhat overwhelmed by the mere idea of the loss of her world, of Harry and Ron and Ginny and everything she'd ever known, Hermione let loose a sob and covered her mouth as if trying to keep it in.

"Everyone ever alive, lives. Perhaps not in the moment you are experiencing, but this does not diminish their importance. They do not fade in significance as your overlapping time with them seems further away," The Keeper counseled, but it was of little comfort to Hermione.

"And when you do what you must, you are in a unique position to overlap again with them," he informed her.

"I'll see them again?" Hermione asked suddenly, eyes shooting up to The Keeper with hope.

"The world is changed," he reminded her. "But yes, from your vantage point, you will see them again."

Hermione steeled herself, knowing her journey would not be an easy one and might take her anywhere and anytime that Rodolphus Lestrange had effected in history. But she had just lost everything, her entire world; she had nothing left to lose.

Wiping away the last of her tears, Hermione looked The Keeper resolutely in the eye.

"Tell me what I have to do," she said.


Author's Notes - Okay, this fic requires a little bit of explanation. I have a tremendous weakness for time-travel fic (and time-travel stories in general) but haven't written one for any fandom in literally decades. A couple of years ago, some friends of mine and I were writing an RPG set in the Marauder-era (those of you who have read "Four Girls Sirius Black Could Have Fallen In Love With [And One He Did]" will recognize some of the OCs here, as they are also based off of the RPG). I loved it. I miss it. And I got to thinking... how fun could it be if I sent Hermione back in time to our version (more or less) of Marauder-era? Well... oodles, at turns out. At least for me. This will be a long story. I hope it will be an ensemble fic, rather than Hermione-centric, and I intend to write several POVs. How long will it take me to write? No idea. How often will I update? Not a clue. Will it EVER finish? Your guess is as good as mine. But what I can promise is this - I will be faithful to the characters as I see them; I will try to tell a story that looks at how little things we do change big things around us; And I will try to show that no matter how much we think we know about people, about eras, about history, there's more to it than we assume.

I hope you stick around and read a bit. If you enjoy it, let me know. If you don't... well, let me know that, too. I can take criticism as long as it's constructive. While this story is totally stand-alone and will not follow the same plot as our RPG, there will be a few lines hijacked from the RPG here and there. If they aren't ones I wrote, I will credit them. From the get-go, characterization credit goes to Kileaiya, Andacus and RJLupinsKat for James, Sirius and Hestia Jones respectively. None of this would exist without our collaborative effort alongside ShyGryff and Celtmama and several others who popped in to write with us from time to time. Thanks for reading!