A/N A rather rare pairing, here, but I personally love it. I tried writing them for my friend (username Natalie Nallareet), and I think that at least the first couple of bits turned out rather well. I had to make this sort of AU, so I have Sherlock and Luna as preteens living side by side in a random town before Luna moved to Ottery St Catchpole and Sherlock to London. Reviews are always appreciated!

Rated K plus for references to violence and slightly graphic blood

Disclaimer I don't own Sherlock/Harry Potter, or any associated characters, events, etc.

SILVER IVY

Everything about her glows. Pale skin, as if lit from below by silver moonbeams, cascades of dark golden hair running over her slim shoulders, bell-bottom jeans topped by a light, floaty shirt, the sleeves of which flare out, its thin material shimmering and reflecting the sunlight as it catches in the invisibly knit threads. And, standing out more than anything else, her eyes, like liquid mercury, wide and bright and intelligent. She's like a shot of starlight among the mulling crowd of the city street, meandering along at a pace that looks like she only partially knows where she's going, half-wandering as she traverses the busy sidewalk.

"Eye out for a girl? Wouldn't have expected it of you," Mycroft chides, lifting his chin superiorly. He's sixteen, several years older than Sherlock, and he knows it, too, flaunts it in a way that always, irritatingly, seems to please their parents sky-high. His hair is neater than Sherlock's, cropped dark and close to his head, and his face is carved differently, starker, grimmer. They have some similarities, though—tall, slim figures, light skin from typically staying out of the sunshine, frosty eyes that scope out the air before them like a hawk's, currently glued to the willowy form of the young girl.

"Hardly," Sherlock sneers through his teeth, glancing up through the tangled mess of his inky bangs to scowl at his elder brother. "She's interesting."

"Interesting, indeed," is the murmured response. "Tell me, what can you see?"

By see, he means read—it's a game of theirs, or as close to a game as the two often-feuding brothers ever share. Notice someone in the street, report as much as their demeanor and attire reflect, compare notes. An exercise, of sorts.

"She's… distracted," he breathes, his eyes narrowing as he takes in the more minute details of her oblivious form. "But not by anything material. Overactive imagination, probably. Irresponsible parents, to let her wander off at this young an age with no one monitoring her, especially since she's so scatterbrained, evident by the un-brushed hair and too-small jeans. Well, irresponsible or occupied, presumably by each other, but if they were fighting she'd be more upset, and she's clearly quite placid, so they must just be as distant-minded as she is…"

"All strikingly obvious," Mycroft drawls, utterly unimpressed by the quick tone of his brother's voice as well as the vocabulary littered throughout it, which is advanced well beyond his age. "Anything else?"

Rather than replying, Sherlock draws his lips into a hard line, watching as the shining girl is sucked away into the depths of the dark-silhouetted pedestrians flitting about, and vanishes like an extinguished match. "Nothing else," he finally confesses. The truth, though he doesn't say so, is that—for once—he wasn't even attempting to deduce anything about her. He was watching, simply watching and wondering. Not wondering about the simple facts easily readable in her face and clothes, but the subtler ones, the workings of her mind that were impossible to discern solely from her appearance.

He ignores the steady stream of more acute observations trotting out of Mycroft's mouth—he doesn't care about what his brother's noticed, because something about the girl beckons him to imagine, not figure out, but truly use his barely-exercised creativity functions to try and know more about her. Almost like she's a story figure, part of a fantasy tale.

There's something unusual about her, and he finds himself intrigued.

The body lies in a pool of blood, the thick, dark crimson liquid seeping from a gaping hole in the center of its drenched chest. The shirt might once have been white, but it's now just as scarlet as everything else, deepening to something near black at the center. Its eyes are wide, dark brown but fogged over with sickening, filmy grey. Sherlock's own eyes widen with fascinated curiosity, but a smartly dressed police sergeant takes that opportunity to step in front of it, blocking Sherlock's view. He growls in frustration, pressing against the damp wall of his hiding place—a tiny alleyway between two buildings, too puddle-filled and rat-infested to ever beckon the attention of any adults. The perfect place for him to observe from.

"Do you think he had a family?"

He starts, his feet scrambling in alarm and splashing the muddy water over his trousers. Mummy will be furious at the stains, but he doesn't care at the moment—he's too busy turning around, staring in amazement at the girl standing behind him.

It's her, the starlight one, and she's gazing straight at him with an easy, appraising sort of expression, her head tilted slightly sideways. She seems fazed by neither the grunginess of the alleyway nor the gruesome scene before them, looking almost at home between the slimy brick walls. Her eyes are even wider than Sherlock remembered, glinting with curiosity.

"Why are you here?" he asks suspiciously, rather than answering her question.

"It's interesting." She shrugs, her eyes flitting over his shoulder, to where the policemen are now waving off the gaggle of gaping onlookers, their faces weary and distracted. "Mum doesn't like me watching the dead people, but I like to think about them. Wonder about them, you know? Like this one, whether he had a family."

"He didn't," Sherlock mutters shortly. "There's a tag on his shirt, very visible from behind, and it's from the cleaner's, so he doesn't have a wife to do the washing for him, or anyone else to point out that he forgot to rip the tag off. His jaw is also unshaved in a very particular spot; no one to tell him about that, either. He lives alone."

"You're very smart," she says plainly, still not meeting his gaze. "I noticed you earlier, in the street with your brother. You two look alike."

She noticed me? He swallows, his mouth suddenly dry. Somehow, she's managed to draw his focus entirely away from the crime scene; she's much more of an enigma than the surprisingly common murder setup. "We don't, really."

"Well, I think you do," she declares, her voice bright. "Oh, look, there he goes…"

Turning back, Sherlock sees that the corpse is indeed being loaded onto a gurney, sealed away in a blazing-lighted ambulance, which wails mournfully as it trundles off, wheels bumping over the uneven street. As if prompted by the vehicle's departure, a light rain begins to mist the air, pattering over the pavement and diluting the vivid red of the dead man's blood.

"I should get home," she muses. "Mum won't like it if I get my hair wet."

"My brother hates getting wet. He always has an umbrella with him, even when it's sunny out."

Her teeth flash in what's almost a grin. "You're funny."

That's one adjective that has never been directed towards Sherlock Holmes, not in all nine years of his life. Funny? Then the girl's expression morphs, becoming suddenly serious.

"You should watch out for Wrackspurts," she advises darkly. "They like intelligent minds, like yours. Your brother already had a couple on his tail."

"Wrack—?"

"You should come to my house sometime. Daddy could tell you all about them. He knows everything about creatures like that. Oh, but…" She bites her lip, looking away in almost guilty frustration. "You can't. You're a Muggle."

"A what?" Sherlock can't remember ever having felt so stupid in his life, but this girl—she's so quick, flies through topics with such rapidness, an impulsivity that he can't quite latch onto, even as each of her words is careful and measured, spun out in a thoughtful, musing manner.

"Never mind. What's your name, anyways?"

"I don't want to tell you," he replies shortly. It's true. He's barely had a single conversation with this strange girl; there's no reason that he should be giving her his personal information. She evaluates him for a moment, then gives a careful nod.

"That's okay. I can tell first, if you'd like. I'm Luna, Luna Lovegood."

The name is perfect for her, almost jarringly so, but Sherlock doesn't comment. The rain is growing more intense, beginning to hit his curly hair and skinny shoulders even with the covering of the buildings on either side of them, and he voices the observation quietly as a few glinting drops coalesce on her forehead. "You should go home now, if you don't want to get wet."

"I should," she agrees. "I'll see you around, then, right? Maybe you'll trust me enough to say your name." She doesn't smile, not with her mouth, but her eyes sparkle, and her step is lively as she darts back up the alleyway, her straw-colored air streaming behind her like a sunlit banner.

He feels the rain much more with her gone, and it suddenly strikes him just how cold it is, carrying the frigid tang of late autumn. Grey washes the walls and street, and he shivers, starting off on his own way. He ought to get home, even though his parents are undoubtedly far from concerned about him. They know that he can take care of himself, even in the rather decrepit town where a street murder is far less uncommon than it should be. Still, the outdoors holds no more interest for him, and so he begins the trudging path back to his house, feet dragging in the puddles and head ducked to avoid the wet, bitter wind, with her voice still ringing in his mind.

He notices the noise outside right away. Perhaps it's because his senses are always more carefully attuned at night, away from the hustle and bustle of daytime ambience, more able to focus on the minute noises and subtle shifts of light that the darkness provides. Even the smallest thing out of the ordinary catches his attention as he lies awake in bed (sleeping is rare, for him), and so it is that he immediately is aware that something's slightly wrong tonight.

It's a faint sound that rouses his notice—a sort of scraping, quick and sharp, outside his second-story window. The Holmes house is nicer than most of those in town, practically a small mansion, and he even has a tiny balcony, but that's not where this is coming from. No, it seems to be out on the grey-stoned wall itself, and, as he focuses on the cold-misted windows, he can see a pale hand press up against it, followed by a pair of inquisitive eyes that gleam silver in the moonlight.

It's her. Luna.

For some reason, he doesn't hesitate before slipping out from under the warm covers of his bed, stepping swiftly over the vintage-carpeted floor and lifting the window. The wood releases a low whine as he shoves it upwards, but nothing loud enough to disturb his parents or Mycroft. And there she is, her breath fogging up in the cool night air, her hair wreathing around her flushed face like a halo of winter sunlight.

"Hello," she whispers, glancing around and quickly pulling herself inside. Dumbfounded, he watches, then glances quickly outside. Pale, flat bricking, crossed over with strands of dark ivy, falls away for two stories before the skeletal forms of leafless bushes take over, obscuring the ground. There's nothing that she could have used as easy leverage, and the vines aren't stressed or torn whatsoever. It's like she floated, like a ghost.

A less sensible boy might have been frightened at this point, but Sherlock isn't. He knows better to believe in ghosts, and Luna is very real, in any case. A bit odd, yes, but nothing supernatural.

"How did you do it?" he asks in an undertone, making sure to pitch his voice so that it can't carry to the other rooms as he slides the window shut.

"Do what? Find you? Get in?" She's rummaging about the room, now, running her hand over the antique dresser, gazing in a nearly enraptured manner at the glass case of pinned butterflies hanging on his dark-wooded wall.

"…Both."

"I can't answer either of them," she replies almost cheerily. "Sorry, but it's against the rules. Maybe someday I'll let you know."

"I can tell, usually. But you're different. You don't work like a normal person."

"And you're very smart," she declares for the second time in the span of their short acquaintance, as though that settles the matter.

He goes silent for a while, watching as she paces around the rest of the room, carefully examining each of the most fascinating artifacts dotted throughout it—a cat's skull, a thick book documenting Jack the Ripper, a few packets of fingerprint powder. After she's made a full circuit, she wanders over to his richly draped bed and sits on the edge, her fingers dancing along her knees as though she can't bear to hold entirely still.

"I like it here," she declares, her voice high and soft in the silence, carrying a vibe of gentle sweetness.

"Don't your parents wonder where you are?"

"Not really, I shouldn't think. They're usually asleep by now, unless Daddy's experimenting, and he was very tired tonight. I thought you'd be, too, but you don't seem sleepy at all."

"I… don't sleep a lot," he explains stiltedly, not offering to elaborate any farther than that, even when one of her slim eyebrows rises in questioning. Instead, he looks down, and she shrugs, hopping off the bed.

"Well, you should. It's not good for you otherwise."

"You're awake."

"I have a reason, though."

"Which is?"

She steps past him, her feet—bare, he notices, the plum carpet showing between her toes—making no noise, and then calmly wrenches the window open on her own. It's much quieter when she does it, barely creaking at all, and he's almost jealous at her clear ability to move stealthily. "I wanted to see where you lived." She raises one leg, hangs it over the edge.

"You're leaving already?" he asks, unable to tell whether the twist in his chest is relief or disappointment. A tiny crease forms between his eyebrows. Unable to identify his own feelings? That's… bizarre. Unhealthy, probably.

"Of course. I was never going to stay that long. Like I said, just wanted to see…" By now, she's perched on the sill, her legs dangling in the open air with the night breeze snaking between them. "Do I get to know your name now, at least?"

"You know where I live, but not even my name?"

A particularly strong draft gusts inside, sending chills down his spine, and causing her wavy curls to flow around her shadowed face like a starlit storm. "Yes," she says simply, her tone matching the sound of the wind.

"…Fine, then." He doesn't know why he's talking, why he's telling her, but it has something to do with her voice. He wants to hear his name in that voice. "It's Sherlock Holmes."

"Sherlock Holmes," she murmurs, and a shiver of pleasure tickles the base of his neck. Her enunciation is rather lovely, clean but not gritty, the syllables drifting out as though her lips are formed of silk and chiffon rather than flesh. "I like it. It's unusual. Mysterious."

She smiles for the first time then, her teeth shining bright as her eyes, quirking into her cheeks, which are hued with a faint blush from the nip of the air. Then, with a tiny wave, she slips out of the window, falling away into the night.

He half-expects the sickening crunch of her body hitting the ground moments later, but there's nothing. Slowly, nervously, he creeps over and peeks out the window. Bricks stretch before him, eventually melting into the frosted bushes, but Luna is nowhere to be seen.

Maybe someday I'll let you know, she'd said.

And you call me the mysterious one?

She comes the next night, and the one after that, until he eventually learns to expect her. Each time she stays a little longer, flopping back on his bed so that her hair streams over the pillows, telling him about the Crumple-Horned Snorkack that she was positive she sighted that day, or the experiment that her father was conducting that nearly blew up the house, or her theory about the stolen jewelry from a nearby retail store. And, for some reason, he finds himself happy to listen. Her words sound different than the buzzing mumble of most people, bright and fresh and new, and she always has something interesting to say. He's beginning to learn that she's just as odd as he is, but in a different way, a way that's less antisocial and more off in her own world.

She's intelligent, though, perceptive, and she notices that he thinks such. On the third night of the second week she's been coming to visit him, she says so, bluntly but cheerfully.

"You think I'm mad, don't you?"

"Why would I?" he lies easily, leaning against the wall. They're sitting next to each other on the heavy-blanketed bed, her propped against the headboard as usual, him perched on the side with his arms wrapped around his knees.

"Because I talk about things that you don't understand. Like the Snorkacks. You don't believe in them, do you?"

He shrugs, reaches out to finger the edge of a coat that he has draped over the bedpost. It's a new garment, only gifted to him today by a rich grandparent, and a very nice one, at that. Dark grey wool, long and sturdy, guaranteed protection against the outdoors—whether it be providing rain, snow, or sunlight, all of which he typically avoided. He adores it, though he didn't tell anyone so, since doing so would be expressing gratitude. He hates looking grateful; it makes him feel weak.

"Ooh, is that new?" Luna asks, peering at the coat. He nods, not looking away from it. "Will you try it on? I bet it looks amazing on you."

At first, he hesitates—why should he model for her?—then decides that there's no use in refusing. It's only a good-natured request, after all, and he likes wearing the trench coat, he'll enjoy it. So he hops off the bed, the mattress bouncing underneath him, and reaches out, pulling its long sleeves over his thin arms and gathering the front up by his neck. It's a bit large on him, hanging off his gangly frame, but Luna looks delighted.

"It suits you," she tells him eagerly. "Perfectly."

"…Thank you," he mumbles in response, ducking away in humiliation to hear the words coming from his mouth. Thank you? Thank you?! He's probably never used the ridiculous, mundane phrase before in his life. But it prompts a small smile from Luna, and her silvery eyes gleam, which makes it worthwhile.

"Here—" She bites her lip quickly, looking around the room as if expecting an eavesdropper, then meets his eyes intently. "You showed me something, now can I show you something?"

"…Yes," he says, slightly confused. "Go ahead."

She slips to her feet and darts over to the window, which he left open to allow the crisp breeze into his stuffy, too-warm room. Reaching out, she plucks a single ivy leaf from one of the vines, bringing it inside immediately. It's still clear green despite the nip of frost in the air, and she carries it over to him quickly, letting it rest in the palms of her hands.

"Look," she says, kneeling down on the carpet. Unable to suspend his curiosity, he does the same, crouching next to her and settling his chin on his knees to watch, securing his hands around his calves. She places the leaf between them, where it shines emerald against the dark purple of the carpet, then slowly runs her finger over it.

Sherlock's eyes slowly widen in astonishment as the leaf glitters faintly, before a new color spreads out from its center, filling the thin veins and stretching over the taut skin of the plant, shifting its hue to pale, shimmering blue-grey. A hint of green still shines through, blending with the new shades to create a new color entirely, which he can only imagine seeing in the depths of winter-sky nebulae, expanses of exploding galaxies and newborn stars only visible through a telescope lens of the highest quality.

"How?" he whispers simply.

"It's magic." Her slim finger wanders around the edge of the leaf, stroking it slowly. "I can do magic."

He shakes his head slowly, and the very instant seems to sparkle, the air between them crystallizing with the rush of a beautiful mystery. Neither of them are breathing, just gazing at the leaf, their lungs quivering with Sherlock's amazement and Luna's pride.

"It's so… pretty," he manages to breathe, the words ghosting out of his mouth, barely making any noise. She still hears, though, and glances up to look at him, his pale face and coal-black curls and shaded trench coat.

"It's your eyes," she explains softly. "I made it the color of your eyes."

He looks up, frozen in astonishment, and then, slowly, manages to smile.

It's the very first night in six entire months that she hasn't come, so of course he's worried. Worry is normal, he reminds himself as the ticking of the clock presses onwards and the window yields no sign of her. You were bound to feel it at some point. There's no reason to be upset.

But, he figures, perhaps the upset is part of the worry. It's unpleasant, horribly so; it writhes in his stomach and creeps up his throat, sour and bitter and sick. Every thought of her glinting eyes, of her rare smile, her wavy hair, is like a white-hot pinprick in between his ribs. And he had things he wanted to tell her tonight, too. He was going to report on the news about the missing baby three doors down, how the child had been recovered but the kidnapper was still on the loose, ask her if she had any suspicions about who could be responsible…

The words still dance around the inside of his mouth, caged without anyone to listen to them. I think it's Mr. Masters from the convenience store, he seems shifty, the back room of his shop has been boarded up for a while now and a few of his shirts have stains on them that look like a two-year-old's spit-up…

But she isn't here, isn't here to listen, and he wrings his blanket between his fingers as the moon swims across the dark, starless expanse of sky. Of course there would be no stars. Exhaustion begins to tug on the undersides of his eyes when the first hints of buttery sunlight tickle the horizon, illuminating the light crust of snow on the frozen ground, but much more demanding is the nausea in his stomach, the anxiety.

She came when she was sick. She came when he was sick. She stopped by and left him a message every day of that week when his family was out of town. So what could possibly be keeping her back now?

Gradually, soft birdsong joins the tentative morning light, and then the rustlings of people waking up in the houses around him. The night has passed, the whole night, and there's been no sign of her.

Where is she?

A rattling comes from downstairs—the mailman. It's Sherlock's job to get the mail, to bring it onto the kitchen table for his parents, but he's tempted to neglect his duty right now, to stay in here and await a sign of her.

But she's not coming. He has to admit that to himself, and the way to do such is to resume his regular motions, to go down and retrieve the stack of papers that'll be sitting on the floor.

So he pushes open his heavy door and darts down the stairs outside, his feet heavier than usual and his hand lingering on the dark, glossy railing. The hallway seems more shadowy than usual, the mound of white envelopes splayed dismally on the dusty carpet. He crouches down, lifts them. The lettering on one of them catches his attention as he rises back up and starts for the kitchen—it's hued dark, plummy violet, shining and practically fresh.

It's addressed to him.

Without any father hesitation, he dumps the rest of the mail on the table that he's reached, and carefully tears his open, shaking out a piece of what seems to be old-fashioned parchment, as well as something else—something smaller.

It's a leaf, an ivy leaf. Glittering greyish blue-green, with crystalline silver around the edges. Perfectly preserved, even though it was cut months ago. Flawless.

His eyes drift down to the paper, then, the curly violet scripture flowing across it.

Dear Sherlock,

I do hope that you receive this letter in good time. I'd hate to keep you up waiting for me tonight, but your mail system is rather slow compared to the one I'm used to. If it does come late, then I'm sorry, but there's nothing to be concerned about. I can't believe it slipped my mind to tell you this when I was last at your house, but Mum did always say that I only remember the most unimportant things.

My parents have decided that we should move away. There are too few people like us in this town. You know what I mean, but I mustn't say the word in case someone other than you is to find this letter. We've found a truly lovely place near the village of Ottery St. Catchpole, and Mum and Dad think it will suit us much better. I never told them that I have a friend here, but I rather wish I did now. I don't particularly want to move, but I'll be going to school in less than two years, so I suppose we wouldn't be seeing each other too often at that point, anyways.

You're the cleverest boy I've ever known, and someday you'll probably be very well-known. With a little luck, perhaps we'll meet again someday. I know I'd like that.

I've put something extra in this envelope, so that you hopefully won't forget me in too much of a hurry. I was tempted to keep it, to remind me of your eyes, but I decided that I'm much more likely to remember you than you are to remember me. Hopefully, both of us will, this way.

I'll always think of you when I look at the moon.

Luna