Disclaimer: I don't own Harry Potter, or any of the characters mentioned below, unless otherwise stated. This disclaimer applies to this and all future chapters in this story.

Fact and Mystery
By: Aya PG-13 ( T ) to R ( M )
Warnings: Spoilers for all six books, especially The Half-blood Prince.
Summary: Summer comes, peaceful in the aftermath of the the events at Hogwarts, and Harry, Ron, and Hermione are working to figure out the first of many mysteries: Who is R.A.B. and where is the real Horcrux that was taken?

"The only words that ever satisfied me as describing Nature are the terms used in fairy books, charm, spell, enchantment. They express the arbitrariness of the fact and its mystery." – G.K. Chesterton

The sunlight made her scar stand out more so than usual on her tanned cheek, a pale line curving from the corner of her eye to her chin, and long-since healed over. Her eyes flickered everywhere, taking in every minute detail in the sun-drenched yard, from the squirrel in the neighbor's tree to the butterfly hovering lazily over flowers dried out from the intense July heat. She appeared at ease as she leaned against the doorframe, back to the air-conditioned house, but her shoulders were tense beneath the t-shirt she wore and her eyes never stopped moving, studying every moving thing like she used to study books.

Light footsteps on tile caused her to noticeably tense moments before a callused hand rested on her shoulder. A chin joined the hand and a pale, freckled cheek pressed against her own scarred one as loose strands of red hair tickled her ear. "See anything out there?"

She shook her head, brown curls cut short swinging slightly. "That's just it," she said, voice showing strains of fear and something else. "There's nothing. Two weeks, and not a single sign of anything has been spotted. The papers are quiet, but even the Muggles are noticing the owls flying back and forth, and you can feel the worry hanging over the entire country. Why haven't there been any attacks?" She sighed. "Something's going to happen soon, I can feel it."

"Don't worry about it until it does, then," he replied, the lightness in his voice sounding forced. "There's nothing we can do to stop it if it's coming, all we can do is be prepared." He patted her shoulder and stepped away. "Come on, close the door, you're letting hot air in. Besides," the smile this time was definitely not forced. "Harry's back."

Hermione felt a similar smile tug at her own lips, a strange pull of muscles after so long without anything to smile for. She glanced around once more, saw nothing that caught her eye, and closed the door to the backyard. The small smile still on her face, she turned and followed Ron further into the house.

It was in the living room that she found the two men, both with their wands out as they pointed to bag after bag and enlarged them. Soon, the entire floor was covered with everything from books to food, and Hermione was glad that they'd shrunk all of the furniture the previous week and stored it in a closet.

Harry looked… well, bad was an understatement, though Hermione knew he would never admit to not eating or sleeping enough. That was Harry, and she'd long since realized that he would do what he needed to do, without thinking about himself first. Still, the dark circles under his eyes were starting to become dangerously dark, and his cheekbones hadn't been quite that sharp when she'd seen him three days before.

None of them had been happy about the task, but they had all agreed that someone needed to go out and get certain things. Harry had been the obvious choice; he was the best dueler of the three, and knew his way around Surrey better. Ron had been eager to go with him, but they knew one person could travel faster and hide more easily than two or three. And with the destination Harry was headed for, Diagon Alley, getting caught was definitely out of the question.

"The books over there are the ones you requested, Mione," he said, drawing her attention away from her thoughts and to the stack of dusty texts by the fireplace. "And I stopped at the store a few blocks over, got more food since we're nearly out," was said with a pointed look at the red-haired man trying to appear innocent as he pulled out the box with his name on it, sent from his mother to the Twins.

There was an envelope on the top of the box, so Ron broke the wax seal as Hermione flipped through her new books and Harry carried bags of food into the kitchen. "Mum says hullo," he said, loudly enough for Harry to hear. "She says the wedding is going to be on the fourteenth, but mum and dad want us there the day before." He dug around the box, searching for something, and grinned when he found it. "She sent cookies, too!"

"The Dursley's get home on the twelfth," Harry said, coming back in for another armful of bags. He caught the questioning look both of his friends sent him before he left the room again. "I called them from a public phone while I was in town," he explained, his voice carrying from the next room. "They're enjoying Majorca, and Vernon says the house better be in perfect shape when they get back."

Ron grumbled something under his breath about fat cousins and ignorant Muggles, but it was lost between the bites of cookies.

Hermione hefted her stack of books, balancing them on one hip. "Well, I think we should be out of here long before they get back, don't you think?" She paused, switching the books to her other hip for comfort. "We'd endanger them just by being in the same house, and, besides, I'm sure Mrs. Weasely won't mind having us an extra day." She moved out of the room, passing Harry as he came back in once more. "I'm going to go put these away, and we should probably start getting everything together. Today's already the ninth." With that, she vanished up the stairs, and the sound of the guest bedroom door closing echoed through the silent house.

Neither man moved for a long moment, waiting to be sure their friend didn't re-emerge. Then, as one, they glanced towards the back door. "Think we can get away with a quick duel?" Ron asked, voicing the question for both of them.

"Who cares? I've been wanting to perfect that wordless Disarming spell since before I left," Harry said, eyes lit up.

Cookies forgotten, Ron rose and followed Harry towards the backyard. "Just watch your slashing hexes this time," he said. "Hermione and I don't need matching scars, you know."

A light laugh, one of the few heard in the two weeks since school ended, drifted up to the window of the woman they were talking about, and she rolled her eyes as she glanced out the window. "Boys," she muttered under her breath. Then their Silencing and Notice-Me-Not charms went up and blocked out all sounds of spells and hexes, and Hermione turned back to her books.

Night fell and Four Privet Drive sank into the shadows, the windows dark. A simple Charm took care of light escaping from the glass, though there was very little of it in the house anyways. The only source of light came from the smallest bedroom, where the three teenagers sat around in a tight circle, focusing on the task before them. The room was a far cry from Harry's normal summer habitat; instead of robes and magazines scattered about, there were stacks of books covering every surface (except the bed, which had been spelled bigger and was currently straining to hold up three heavy school trunks), parchment and ink in neat little piles, and not a sign of a broomstick or Quidditch logo.

An area had been cleared at the foot of the bed, which is where the trio sat at the moment, backs hunched over dusty books and old newspapers. Between the three, in the center of their circle, was an area empty except for a golden locket and a small square of paper with writing on it. The writing was what the three were focused on, studying the words until they'd been memorized.

To the Dark Lord

I know I will be dead long before you read this

but I want you to know that it was I who discovered your secret.

I have stolen the real Horcrux and intend to destroy it as soon as I can.

I face death in the hope that when you meet your match,

you will be mortal once more.

R.A.B.

"I'm beginning to wonder," Hermione said under her breath, one hand absently rubbing the scar on her cheek, the only sign she had from the battle at Hogwarts a few weeks before, "if this R.A.B. person wasn't a Death Eater at all." She put down her copy Notable Names of Nineteen Eighty-Two, and sighed. "I mean, maybe it's someone else altogether? Maybe the initials aren't a name, but a title of some kind?"

Ron groaned, putting down his own book. "You're not serious, right? You mean, start from scratch?"

"I just mean—

"Sirius! That's it!" Harry's voice cut Hermione's off as he slid his book off of his lap and quickly rummaged around a pile behind the desk chair, returning to the circle with a leather-bound tome in his hands.

Hermione blinked, perplexed at Harry's sudden excitement. "What good is Records of the Most Ancient House of Black going to… Oh." She sat back, eyes wide. "Why didn't I think of that?"

But Harry was too busy flipping through the end of the book to pay much attention. "Where is it, where is it?" he muttered to himself, scanning page after page. "He told me there was a copy of his family tapestry here, where is it? Ah ha!" he stopped, triumphant, on a page with dozens of tiny names connected by thin black lines.

"Um, Harry? 'Mione?" Ron looked between the two of them, confusion written all over his face. "Someone wanna let me know what's going on?"

It was Hermione who answered, as Harry was once more flipping through pages. "R.A.B… the last name Black clearly fits, and the Black family has always prided itself on being pure of blood, and aligned themselves with You-Know-Who." Hermione, once more, sounded like a textbook. She opened her mouth to continue, and was once more cut off by Harry.

"Here, I knew it was in here. Regulus Black." He bent over the book, eyes squinting to read the tiny text. "Sirius' brother, younger by a year, sorted into Slytherin, blah blah blah." He trailed off and looked up, grinning. Neither Hermione nor Ron shared his enthusiasm. "It must be him!"

"Harry," Hermione said, gently, "there must be hundreds of R.A.B.s out there, and it could have been any of them, maybe someone not in the Black family."

But Harry was shaking his head. "It is him," he said. "It's all coming together now… I don't know why I didn't think of it before. Regulus Black, Sirius was telling me about how he was a Death Eater, and he tried to back out, but Voldemort," he rolled his eyes as Ron and Hermione winced, "he killed him, instead, because once you join the Death Eaters there's no going back."

"But that doesn't explain how he knows about Horcruxes, Harry, let alone why he would have wanted You-Know—fine, Voldemort—why he wanted him to be mortal."

Harry was on a roll, now, eyes wide with hope for the first time in a while. "Yes, it explains everything! You weren't there, when Dumbledore," here, he paused over the name, breath catching in his throat, but he pushed on, "brought me to persuade Slughorn out of retirement. Slughorn started going off on how he'd wanted Sirius in his house, and he'd gotten Regulus when he entered, but he'd wanted the matched set. And if Regulus was in his stupid little Slug Club, couldn't he have learned about the Horcruxes, like Riddle did?"

Hermione caught on, now, "You do have a good point, Harry," she said. "There are so many things to consider though. How did Regulus find the Horcrux? Why didn't he know about the others, and think there was only this one? And where did it go? Did he destroy it, or is it hidden somewhere?"

They both fell silent, pensive, leaving Ron to look back and forth between the two of them with a mixture of surprise and, still, confusion. He glanced down at the locket and the paper once more, frowned, and looked back up.

"I have an idea," he said, tentatively. "The locket… I think I might know where it is."

Two sets of eyes were immediately focused on him, and Ron found himself flushing under their gaze.

"You remember cleaning Headquarters last year, and Mum made us clear out all of those room upstairs?" he asked. He got two affirmative, though impatient, nods. "Well, d'you remember all that junk we found? Loads of it, and most of it useless. Well… there was that gold locket we found, the one that nobody could open, in the Drawing Room. And I just thought… well, it's a long shot, but…"

He found himself with an armful of Hermione, who was hugging him tightly. "You, Ronald Weasely, are brilliant," she stated. "Now, where would that locket have gone? Could it still be in the house?"

Harry shook his head, "No, Dumbledore cleared the house out at the beginning of last summer, and he would have recognized the locket if he'd seen it."

"Then maybe it's still there?" Hermione suggested.

"Dumbledore wouldn't have let them leave a magical object in that house, when Death Eaters could get it."

Ron asked the question they were all thinking. "Then, where is it? Who else would have stuff from Headquarters? Especially something like that, a useless gold locket that you can't even open?"

"I know who has it," Harry said, standing and setting the book he still held on the desk. "Who else would have taken something like that? Someone who would sell it for a few sickles, for his own gain. Someone who was known to have stolen things from that house. Mundungus Fletcher."

Please review, and let me know what you think. Even one word is fine, if just so I can do better on the next chapter.