Harry tugged at his bow tie, squinting in the mirror perched on Hermione's dresser and wondering if it was jaunty or merely horrendously askew. He'd never worn Muggle clothing like this before, the most formal attire he had donned in the past having been a pair of suit trousers originally belonging to Vernon that he was forced to wear for the last few weeks of the summer he turned 10 when his last pair of jeans became more hole than fabric - and those were more cavernous on him than they were dapper. They reached his armpits, for Merlin's sake.

"Hermione," he muttered, "is this really necessary? It's a bloody barbeque, do you seriously think everyone's going to be dressed like this?!"

Hermione turned from the desk she was hunched over, trying to finish an essay she'd set herself comparing Muggle art from World War 2 to the spells created during the Dark Days of the First Wizarding War. Removing a quill stuck in her bushy mane and letting it fall around her flushed face, she gave an exasperated sigh. "I just think you look nice! And anyway, you don't want me to be the only one dressed up, do you – I got this dress last Christmas and if I don't get a chance to wear it soon then it'll be too small and you know I can't use magic to make it bigger until I'm of age."

Harry eyed her in the mirror, frowning so hard that his scar puckered even more than normal. Noticing this, he pushed his hair forward and hoped it would take a hint and magically grow slightly before they got downstairs, not that it ever worked like that. Grow from bald to ear length in a night when Vernon forced him to cut it, sure, but never when he actually wanted it to. Turn blue seemingly for no reason but to wind up Petunia and get him in trouble for a month while it resisted every hair dye she chucked on it? No problem. This? No. Bloody unconscious magic.

Hermoine looked so forlorn gazing back at him that he groaned, rolled his eyes and acquiesced – "fine, but can you please help me with this thing? Dudley and Uncle Vernon use clip on ties and it's not like I've ever even worn those, so how do you expect me to make this work? Where did you get it, anyway?"

Jumping to her feet, she skipped over to him, her despondency gone so quickly that Harry suspected it had all been an act to convince him, but before he could accuse her of this, she was fiddling with the fabric and getting it to behave itself so quickly that if he hadn't known better, he'd be expecting the Ministry to descend in swarms to arrest her for underage magic. "There! And it was my Grandad's I think, I found it in a drawer."

"Hermione! Harry!" came a call from downstairs, then again a little louder – Mrs Granger must have come to the bottom of the staircase, and if her tone of voice was anything to go by, was of the opinion they needed to hurry up. This was confirmed by the sound of footsteps getting louder until there was a sharp rap on the door, which immediately swung open with no response needed. Standing there with her hands on her hips, Hermoine's mother looked decidedly comfortable in a pair of jeans and a cosy looking yellow jumper, and going by her swiftly controlled facial expression as she gave them both a swift up and down, was more in Harry's camp when it came to dress codes. "You both ready yet? I need some help with the quiches!"

"Sorry, Mrs Granger," said Harry, taking one last desperate glance in the mirror in case the situation had changed while Hermione was fussing over him – to be fair, he looked less lopsided, but that was the only improvement – and walking over to her with his face as straight and unpanicked as he could manage. Hermione followed him, twisting her hair up with a clip instead of a quill this time, and gave him a look that he supposed was meant to be sympathetic but came across altogether more self satisfied that she'd got her way.

Downstairs, Hermione's father was visible through the open French doors, bent over a barbeque that was smoking a bit more than Harry thought was normal, and was being given a wide berth by the assortment of Granger relatives that was beginning to swell at the edges as more guests came through the passage to the side of the house, clutching an array of offerings to be cooked on the coals – or, as Hermione had told him had happened the last time Mr Granger had been left in sole charge of the barbeque, burnt to a crisp and then doused with ketchup to be politely choked down.

"Harry!" he called, the tone of his voice confirming the nervousness his posture had already given away, "fancy helping me with the sausages?"

Leaving Hermione and her mother arranging mini quiches that were perfectly browned and smelling decidedly more appealing than the current garden situation was promising, Harry joined Mr Granger on the patio, receiving a pat on the shoulder. Looking around to make sure that his relatives weren't in earshot, Mr Granger leant in and whispered "look, old chap, you don't happen to know any… tricks, if you know what I mean, that might make this a bit easier?"

"Er, sorry, sir," Harry mumbled, casting a glance sideways at the chef's flustered, slightly sooty face, "we're not allowed to use ma –"

"Shh! The family are just over there!"

"- um, that kind of thing outside school… Didn't Hermione – "

"Yes, yes, I know, I just… tarnation, when do you come of age again?"

"At seventeen."

Mr Granger sighed. "At least we'll be able to make it work for Hermione's eighteenth, I suppose."

Unsure what to say or do, Harry picked up a sausage and went to put it on the grill before it was snatched from his hand by someone who had sneaked up behind him. "Oi!" he said instinctively, half turning around before remembering himself and hoping he hadn't just snapped at some revered Granger relative, then seeing a young man peering at him through narrowed eyes and twirling the stolen sausage around his fingers.

"Harry, is it?" said the stranger, his eyes flicking up Harry's face to his forehead and widening slightly. "Interesting scar you have there…"

"Um, yes," Harry said, resisting the urge to start trying to flatten his hair against his forehead or run upstairs to try and find some of that skin coloured paste Hermione was using on her face earlier to cover it up. "Car accident when I was a baby."

"Really?" the man replied, raising his eyebrows and smiling slightly, "the kind of accident that shouldn't be named, was it?"

As Harry dithered, not sure if he had heard correctly, his eyes slipped down to the sausage still being twirled between the stranger's fingers, to see it was steaming hot and perfectly cooked. Without breaking eye contact, the man took a bite, turned slightly and yelled through the French doors, "HERMIONE! Need a word with you!"

A tray of quiches preceded Harry's best friend as she emerged from the house, her hair already coming down from the clip and her lips set. "Bernard, for the last time, no, there are NO last year girls at my school who are, as you put it, single and ready to mingle, so if you could stop asking me –"

"Are you Hermione Granger?!" Bernard interrupted.

Nonplussed, Hermione deposited the tray on a table by the barbeque, thought better of it and moved it to one a little further away, before putting her hands on her hips much like her mother had not so long before, and replying "last I checked, yes."

"No," Bernard said, stuffing the last bit of the sausage into his mouth and grabbing her by the hand as he threw an arm around Harry's shoulder and began shepherding them to the end of the garden where a small group of other relatives were sat, a little away from the main throng, watching him with their eyebrows raised, "I mean, this is Harry Potter, right?"

As he said that, one of the girls sitting in the confused looking circle stood up and was hastily tugged back down by another girl who looked disconcertingly like a blonde Hermione. The actual Hermione looked at Harry with her eyes wide and opened her mouth like she was going to say something, but before she had a chance, the girl who was now being held in her seat said in a loud whisper, "hold on, you're Hermione Granger?!"

They reached the group, which immediately closed ranks around them. Harry peered over their shoulders, wondering how the rest of the family were going to react and hoping Mr Granger would intervene before he stopped short, "wait, you know who I am?"

"Yeah, yeah, The Boy Who Lived and all that, but little Hermione is that Hermione?!" the girl continued, finally getting free and bouncing out of her seat. "I thought she was at some boarding school for swots, all this time she's been a witch?! You're at Hogwarts?!" she directed at Hermione, who was for once lost for words. "I wanted to go to Hogwarts but my bloody parents moved to France when I was nine so now I have to wear that stupid blue uniform and prance around, it's not fair!"

Harry shot a glance at Hermione, who had freed her hand from Bernard's grip and took that as a sign it was okay to slide out from the arm still slung over his shoulder. "So, um," he interjected, immediately wishing he hadn't when the eyes of the group all swung back to him, "does this mean you're, I mean –"

"Witches, yeah," said the blonde lookalike, before being punched on the shoulder by another boy who couldn't have been more than eleven, "ouch, sorry, Andy, and wizards." She glared at him as she rubbed her shoulder, pursing her lips. "He just got his acceptance letter, Hogwarts of course."

"Stop being so bitter, Lucy," Bernard chided, "you just wanted to go there because you fancy Dumbledore. She's got a thing for old wizards," he told Hermione and Harry in an aside, before Lucy took inspiration from Andy and gave him a whack. Ignoring her, he turned back to Hermione. "Seriously, though – I can't believe we didn't realise. Thought it was just a weird coincidence 'cos every time we saw you, you were just still so… well, boring."

If looks could kill, it wouldn't be just the wizarding justice system Hermione would need to worry about, Harry noticed as he discreetly patted her on the back, wishing as much as Mr Weasley had that Ron and his family hadn't been busy. He wasn't sure he'd be able to hold her back by himself and even though the rest of the family seemed somehow completely oblivious to the drama unfolding, that might be pushing it a bit far.

Noticing Harry glancing over again at the Muggle contingency, an older wizard who had been eying the pair of them over a copy of The Daily Prophet snorted and said "don't worry about them, we've got a charm cast over here. We're not invisible exactly but they won't notice us. Can teach you it later if you want," this last directed at Hermione. "Ministry won't know it's you casting it with all of us around. From what you two and that ginger kid – " Hermione blushed at this, and Harry did a double take then pretended he hadn't noticed " – seem to be getting up to last year or so – " he brandished his newspaper "- might come in handy."

"Wait," Harry said, his brain working in overdrive. "This means…"

His face broke out into a huge smile, and he spun around, breaking free of the group which immediately closed ranks around Hermione and started buzzing excitedly. "Mr Granger!" he called, making his way back over and sliding his hand into his pocket, "you wanted help with those sausages?"