Disclaimer: I own Ellie Longbottom, but nobody else.

For my amzing twin, Beth (Ella-Bethh), and to her newly-minted fiancée Bri (Miss UnBrilievable), because they're about to get married and I'm so happy for them! :D Also, because Beth requested this ages ago and I finally got the inspiration to finish it.

With the prompts 'streetlights', 'mattress', 'collide', 'soulmate', and "What is that on your neck?" (said by Harry) from Beth, and also the prompts 'jam tarts', 'sparks, 'gravity', and 'connection', from Beth's Prompts that I claimed a while back but unclaimed but decided to use again :)

Everything starts simply, with a beat of a butterfly's wings, with a whisper floating on the wind, with a boy and a girl who play in the gardens, who laugh and talk and dream, who spill secrets and share ideas, who defy gravity and shoot for the stars.

And then that butterfly sparks a hurricane of tested friendships and broken hearts and the agonizing turmoil of being a teenager in love.

(All's fair in love and war, after all.)

Potter-Weasley-Lupin-Longbottom-Scamander sleepovers are, if Ellie's being completely honest, simply the most entertaining event in the entire year.

And not only because they lead to things such as Teddy and Victoire getting engaged (because only Teddy would propose to a girl at a sleepover with her baby cousins) and a prank war between the Weasley cousins (Lily always wins. Always.) and delicious cooking courtesy of Roxanne, the bona fida chef of the family.

Ellie stifles a yawn as she wanders into the kitchen, unable to sleep becaue of the noise the younger kids were making in the next room over, playing Truth or Dare or something. For being such a large mansion, she muses, Percy and Audrey's home had rather thin walls.

Entering the kitchen she makes a beeline for the fridge, delighted to find that there are still some leftovers of Roxanne's world-famous jam tarts in there. Reaching inside, she takes one of the tarts and pulls it out so she can eat in in the relative peace and quiet of the kitchen.

"'Ello, Ellie!" interrupts a familiar voice, and Ellie nearly chokes on the jam tart before whirling around to find herself looking at her best friend as he bounds down the stairs in his pajamas, looking far too hyper for this time of night.

"James, what are you doing up and bouncing around?" she demands, hiding a smile when he winks at her and nearly collides with the counter. "Did you have sugar before going to bed?"

"Erm," James grins sheepishly, "do ten sugar cubes count?"

Ellie stares at him in alarm. "Ten? Merlin's beard, you should know better! You Potters really don't hold your sugar well."

James opens his mouth to protest, only to be interrupted by Lily squealing something about pink panda bears upstairs in her room, and quickly closes it, looking bewildered. "Well, I guess. But you can't blame me. It's the sleepover. I'm allowed to do crazy stuff!"

"Keep your voice down," she tells him. "Don't want to wake the kids up, do you?"

"Most of them are already awake," he retorts. "Who sleeps in a sleepover, anyway?"

"I was trying to," Ellie giggles. "But I got hungry."

James's eyes finally spot the jam tart in her hands. "Oh, those are amazing. Roxie's, right?"

"Indeed." Ellie quickly holds the jam tart out of his reach. "And, no, you can't have a bite. I'm hungry, and I need this so that I'll sleep well."

"That doesn't even make sense," he complains, pouting. "Please, Ells? What do I have to do for a bite of that?" His blue eyes are wide and imploring, and Ellie knows she'll give in sooner or later, because he's James and he's her best friend, and when he's looking at her like that, she kind of feels like melting under his gaze.

"I don't know, take off your shirt?" she suggests sarcastically, but she probably should have known better than to be sarcastic around James – she's not entirely sure he even knows what the word means, let alone not to take a sarcastic comment seriously.

"If you insist," he tells her, grinning cheekily, and reaches to pull off his shirt.

"N–no, don't," Ellie interrupts quickly, leaning over and grabbing his hands to lower them down. "I was joking, James. Honestly, for a prankster, most jokes seem to go straight over your head."

"That's because I can't differentiate between your jokes and your obvious desire to see me shirtless," he teases, lifting a hand to snag a coppery-red curl of hers and examine it under the shine of the streetlights outside the window

"Shut up," she murmurs, trying to sound authoritative and failing rather miserably because his sugar-and-pineapple breath is drifting across her cheeks and his hand is warm against the side of her head and she really can't concentrate when he does that. "I'm still not giving you the jam tart."

"Too late," James grins, letting go of her curl and darting away from her before she has a chance to look down and see that he's broken the tart in half with his fingers and run away with it. "Sorry, Ells, but you know me and jam tarts."

"You're incorrigible," she informs him, smothering a giggle when he shoves the whole half into his mouth. "I can't imagine what your multitude of girlfriends have seen in you, between stealing food from your best friend, shoving it down your throat – "

James swallows the tart and flashes her a grin. "I think you're jealous," he proclaims cheerfully, "of my multitude of girlfriends."

Ellie gapes. "I am not. What gives you that idea?"

"For starters," he smirks, leaning across the counter, "you never do seem to like my girlfriends. And when Mara started going on about us being soulmates when I dated her, I remember you glaring at her. Not to mention, any time I flirt with a girl – "

"Oh, shut up, James," she orders him, stepping back and trying to ignore the butterflies in her stomach that always start dancing whenever he's in close proximity. "I'm not jealous of your girlfriends. I've never been jealous of your girlfriends. Why would I be?"

He drums his fingers on the counter. "I don't know. Maybe you like me."

"Of course I like you."

"You know what I mean."

Suddenly, it feels like the room temperature has increased without warning, because James is looking at her, really looking at her, and his eyes are the brightest shade of blue she's ever seen, and she kind of has to wonder how he could have possibly not noticed that not only does she like him (in the way he means), but somewhere along the line of their crazy friendship, she's fallen head over heels in love with him.

"Ellie," he breathes, and then he's on the other side of the counter, one arm wrapping around her waist and the other tucking a stray curl behind her hair. She has to remember to breathe when he leans down, angling his head, and without even thinking about it, she tilts her head, her hands fisting in his blue shirt.

And then his lips meet hers, and she forgets pretty much everything at the taste of sugar and pineapples and jam tarts in her mouth and the feel of his body warm against hers, the connection between them real and intense as he kisses her like she's never been kissed before.

"Maybe we should – ah – " James pauses to catch his breath when he draws back, leaning his forehead against hers, " – take this to my room?"

His smile is sweet and enticing and so very James even as he peppers kisses down her neck, and Ellie nods, wishing only that they had done this sooner so she wouldn't have been deprived of his kisses and love for seventeen years running.

When they make it to his bedroom, which he's lucky enough not to share with anybody for this sleepover, as Louis and Fred are sharing another room, he pulls her down onto his mattress with him, his lips everywhere he can reach without moving too much, his hands wandering up her nightgown in a way she would have considered too forward had he been anybody but her best friend.

"Our parents," she gasps against his mouth, "are going to kill us in the morning."

"Only if – " James groans as she switches her attention to his throat, her kisses hot all over his skin, " – if they find out."

With a wink, he draws her back into another deep kiss, and as midnight bleeds into dawn, Ellie finds herself laying in his arms, half-asleep, thinking that this was definitely the best sleepover ever.

Of course, the semi-secret is gone when his father unceremoniously drops in to check on him in the morning, but even Harry's horrified, "What is that on your neck?" to his blushing son isn't enough to ruin the joy she feels. Maybe not even her parents grounding her for life can do that.

(It's not like he isn't skilled at sneaking out to see her, anyway.)

Author's Notes: Don't favorite without reviewing, please and thank you :)