Disclaimer: the wonderful wizarding world of Harry Potter does not belong to me.

When Holly arrived outside the fifth-floor classroom opposite Erasmus the Eloquent's portrait (he was indeed wearing a very strange pink hat, covered with tassels and small pieces of mirrored glass), tugging at the hem of her skirt so it fell straight, she could hear faint music coming from the other side of the door. Clutching her gift for Sirius in one hand, she raised the other and knocked much more loudly than intended.

The door was opened a few seconds later by Peter, who presented her with a shiny paper party hat on elastic. "Hello! Come in, come in!" he cried, more enthusiastic and talkative than she'd ever seen him. She followed him into the classroom and was greeted by the sight of Remus and Sirius lounging on chairs, James and Lily chatting by the window. Spread across three desks was an assortment of food and drink, 'liberated' from the kitchens, along with several bottles of Butterbeer - that would explain Peter's exuberant welcome. In one corner, a record player was belting out a song she didn't recognise. Candles were dotted around the room, their flames flickering slightly, some of them a bit too close to the decorations for comfort.

"Holly! You made it!" Lily called, waving at her. Smiling, Holly approached and kissed her quickly on both cheeks, then tucked the present under her arm and put the party hat at a jaunty angle over her curls. "You look lovely," Lily told her.

Holly smiled. "Thanks, cara. You too." She liked Lily's pretty green dress, though it was a bit too long for her taste, skimming her calves. James reached out his hand, and she shook it formally. "Signore Potter, thank you so much for the invitation."

"My pleasure, Miss Hartwell, absolutely my pleasure," he said, grinning widely. "Help yourself to refreshments."

As if on cue, Peter appeared at Holly's elbow with an opened bottle of Butterbeer, offering it up. She placed her hand gently on the mouth of the bottle and shook her head. "Thanks, Peter, but-"

"She doesn't drink that stuff," came the sound of Sirius's voice, smoothed by Firewhisky and pleasure at the fact that he was the centre of attention that evening. Holly jumped; she hadn't heard him approach across the wooden floor. He was standing on her other side, offering her a glass of the warming amber liquid. "This is more to your taste, right?" he asked, looking at her over the rim of the glass with his silvery eyes.

Why did it feel like he was asking her about something other than drink preferences? Dismissing the thought, she took the glass from him and exchanged it for her present, tucking the roll of parchment into his open hand. "Happy birthday, Sirius."

Mystified, he broke the wax seal and unrolled the parchment, his eyes scanning the words within. A small frown crept over his brow. "What is this?" he asked.

"I didn't really know what to get you," she began, clutching the glass of Firewhisky tightly in her hand. "I noticed you swear a lot, and I don't like...what is it…'Merlin's pants', or whatever you say when you're annoyed? I thought it might be funny to give you this. It's a list of all the curse words I know, and all the languages I know them in. Phonetic spellings, too. You could, uh, broaden your vocabulary." Her accent was thickening with every word she said - she wished there wasn't such an obvious outward sign of when she was nervous.

There was a moment of silence, then Sirius burst out laughing, clapped her on the back and pulled her into a brief hug. "Holly, that's brilliant," he said. "Thank you." Without thinking, he kissed her forehead, making her blush, then took her free hand and pulled her over to where the others were now congregating. She followed and sat in an empty chair, sipping her Firewhisky as she watched the boys poring over the parchment, laughing and trying to pronounce the words with some difficulty. Her stomach rumbled slightly, and she pointed her wand at the snack table, summoning a sandwich. She ate it quickly, listening to the new song that was now playing.

Lily leaned over and clinked their drinks together. "Nice idea with the list, Hols," she said, smiling. Her green eyes were shining in the candlelight and her freckled cheeks were slightly flushed from the alcohol. "Very clever. They'll be looking over that for weeks."

"I can't wait to hear them trying to use the words in conversation," Holly replied. She scooted her chair slightly closer to Lily's, and they started chatting about other things; classes, homework (they didn't dwell on that topic for long), Christmas, the next Hogsmeade trip. As always, their conversation was easy, and time flew by, the candles glowing bright orange and gold as the classroom grew darker.

After a while, Holly registered the music again, a different song this time - one she'd never heard before. "Is this smaghi...um, Muggle music?" she asked, nodding towards the record player.

"Yup - the records are mine. I had to enchant the player so it worked with all the magic around, but now it changes the songs automatically. Like a jukebox." She didn't notice Holly's blank expression at the strange word, and instead took a careful swig of Butterbeer. "Do you know much Muggle stuff?"

"I've heard a few things, but not a lot. I spent my childhood with private tutors, my adolescence at L'Accademia. Not much of a chance to experience the Muggle world, or British music."

Lily nodded in agreement. "I suppose not. Maybe I could lend you a few records, huh? You can have a look through if you want."

"Yeah, alright." Holly wandered over to the record player and started picking through the records in their thin cardboard sleeves, pulling one out of the box every so often so she could see the artwork. She recognised the names of some of the artists, but not as many of the songs themselves.

She was just examining a sleeve with four people on it, two men and two women, squashed up against a snow-covered window under the word ABBA, when a large hand appeared on top of the picture.

"You don't want to listen to that," Sirius said, and Holly whirled around then smacked him on the arm.

"Stop sneaking up on me!" she snapped. "You keep tiptoeing around and making me jump."

He grinned at her, not at all sheepish. "Only because it's funny when you're shocked. Your eyes go all big and round and-" he stopped, then cleared his throat. "Sorry."

Holly narrowed her eyes at him. "As it is your birthday, I will let it go this time." She brandished the ABBA record at him. "And why shouldn't I listen to this?"

"It's rubbish," he said dismissively, already rummaging through the box for an alternative, which he quickly found and held aloft triumphantly. "Behold! The dulcet tones of Phil Lynott."

Holly was about to ask who that was, but she was interrupted by a bouncing bassline and the sound of people snapping their fingers to the beat. Sirius was already off, spinning away past the empty desks, jigging around on the balls of his feet. Watching him, she couldn't help but be slightly impressed - the man had rhythm.

"When I passed you in the doorway," he sang, looking right at her, "well you took me with a glance. I should have took that last bus home, but I asked you for a dance…" He held out his hand. "Come on Holly, dance with me!"

She laughed. "Why should I?"

He shrugged, then shimmied towards her and away. "Because it's a party. People dance at parties, right?"

"Not like that!" She gestured to his movements, laughing again as he attempted a sort of pirouette and almost fell over. Across the room, the others gave him a round of applause, and he bowed briefly.

"Well, it's my birthday, and I shall make it a rule that anyone can dance however they want!" he cried, receiving another raucous round of applause.

"So what if I want to dance on my own?" Holly asked coyly. She hadn't known she could be coy; that was interesting. She felt strangely confident, certainly confident enough to have a bit of a flirt. Maybe it was the Firewhisky, maybe she was just having a good time - she didn't know for sure, but she liked it. It was nice to just be having some fun, without thinking about where it might lead or how they might all feel about it tomorrow. She crossed her arms and looked at Sirius from under her lashes, challenging him.

Sirius grinned at her and raised his eyebrows. "That, m'dear, makes you the exception that proves the rule." Gracefully, he moved towards her and took her hand, giving her a moment to slip out of his grasp and say no. Instead, she smiled at him, and he led her onto the impromptu dancefloor.

After watching them, James tentatively invited Lily to dance with him, but she turned him down and took Remus's hand instead, leaving James sputtering in disbelief as they joined Holly and Sirius. Not to be outdone, he followed with Peter in tow a few seconds later; their height difference was bordering on ridiculous as they held each other in a tight clinch and strutted around performing a dramatic tango that wasn't at all in time with the music. Lily tried to ignore him while avoiding Remus stepping on her toes, swaying from side to side, but she couldn't stop glancing their way.

Sirius was the same - dancing with Holly, he was trying very hard not to stare at her, but she hadn't made it easy. He'd only ever seen her in her uniform, or that horrible green suit from when they'd first met, so seeing her laughing and dancing in a pretty blue dress and brown boots, curly hair swinging, comfortable and enjoying herself...he couldn't help but smile. She was a good dancer, too; it was the kind of thing you had to learn when you were brought up in a well-off Pureblood family. He threw out his arm and spun her away, bringing her back to face him just as the record changed by itself.

A slow piano introduction played, and Holly froze. Sirius frowned at her questioningly, but she only shook her head. "Are you okay?" he asked in a low voice.

She nodded quickly. "Yes, just...I wasn't expecting us to slow dance."

"We don't have to, if you don't want," he said, flashing her another easy, reassuring grin. Despite his words, though, they had ended up swaying slowly on the spot, simply because they hadn't stopped talking to each other. Neither of them paid any mind when Sirius's right hand slipped further round Holly's waist and he pulled her slightly closer, the two of them dancing as a couple as if it was the most natural thing in the world.

The music swelled, and Holly felt a thrill run down her spine. It was all very well telling herself to treat Sirius as a friend, but she couldn't deny the little jolt of happiness she felt every time he smiled at her, which simultaneously made her feel like a blushing idiot. And now they were dancing together, slowly and intimately, while the woman on the record sang about how nobody does it better. She glanced up at him, feeling her face grow hot, like it always seemed to lately when she met his gaze. There was something different in his eyes, something that had never been there before, or that she'd never noticed before - she didn't know how to describe it, but she didn't want to look away. She was stood close enough to him to smell his aftershave, a heady but strangely delicate scent that she couldn't quite place, combined with the lingering smell of Firewhisky on his breath.

"The way that you hold me, whenever you hold me, there's some kind of magic inside you…" The music flowed around the room, and the world around Holly and Sirius shrank until it contained only them, trying not to stare into each other's eyes and failing miserably.

"This is a nice song," Sirius said quietly.

"I've never heard it before," Holly admitted. She slid her hand up from Sirius's shoulder to hold the back of his neck. "I think that I would prefer 'Life On Mars'," she said, and they shared a secret smile.

Another few seconds of silence passed between them. They had actually stopped dancing now, and were just standing still holding each other close while the song faded into nothing, but they had barely noticed.

"Did I thank you for my present?" Sirius asked, breaking the quiet. His voice was huskier than usual.

"Yes, you did. I'm glad you liked it - I thought maybe you'd think it was...a bit stupid. Immaturo." Holly bit her lip and looked away, glancing down at her feet.

"What? No, it's brilliant," he said again. "I mean, we can use it loads of ways, and it's funny, and I had no idea...you're so smart, Holly. Really, really smart." He dropped her hand, but only to lift her chin up with his finger so he could see her face. "Thank you. And thanks for coming to the party."

Holly marvelled for a moment - how strong and strict her convictions had been just a few days before, when she'd been assuring herself that she could be happy just remaining friends with Sirius, not letting her feelings for him come into it. Now, in his arms, she could feel her resolve starting to crumble; half of her wanted to break away from him, the other half wanted to step closer and see if his lips felt as soft as they looked…

Luckily, Sirius made up her mind for her.

She had been kissed before, but it crossed her mind when Sirius closed the gap between them, at last, and captured her mouth with his, that she had never been kissed properly. Never so sweetly, like he was trying to say something important without any words. Instinctively she stepped closer and wrapped both arms around his neck, letting her fingers curl into his hair, and he responded with a small groan.

When they broke apart, they were both gasping for breath, and Holly could feel her legs shaking a little.

"Oh," she said breathlessly, at a loss for words. Her lips felt tingly.

"Did I do something wrong?" Sirius asked, stepping back slightly. "I just...in class the other day, your Patronus…"

"What about it?"

"It's...the same as mine," he confessed after a pause. "I mean, once I got over the shock I was kind of happy, you know, that you might feel that way about me, but I didn't want to push anything in case it was just a coincidence, or you didn't actually know how you felt about me, but then I thought, fuck it. It's my birthday. I like you. I wanted to kiss you." After this long speech, the wind seemed to go out of his sails slightly, and he looked a bit embarrassed. "Was it...okay?"

In response, she kissed him again, more slowly this time. He tasted sweet from birthday cake, and hot from the Firewhisky; vanilla and spice mixing together deliciously. Her resolve had entirely vanished now, and she found that she didn't really care - kissing Sirius Black was much nicer than denying she had any romantic feelings for him. She would have quite liked to keep doing it, in fact, but she suddenly remembered that there were actually other people at the party.

Breaking away from Sirius abruptly, she whirled around to apologise to the others...only to find that they had left. She and Sirius were alone.

"Where did everybody go?" she wondered aloud.

"I think they wanted to give us some time alone," Sirius said, pointing to the table that still held remnants of food and some empty bottles. Propped up against a pile of plates was a folded napkin with a cartoon heart drawn on it, pierced by an arrow, with their names entwined inside it. Someone (probably James) had written underneath:

Happy birthday, mate. Enjoy getting to know each other (nudge nudge), and don't spill your drink down her dress.

Holly - don't let him be an idiot.