The inside of the Diagon Alley Auror station – which was little more than a glorified hut – had been decked with tinsel and pine boughs in an attempt to make it festive, and a tartan-patterned tin full of Molly Weasley's homemade shortbread sat next to the teapot.

Harry was miserably cold, despite wearing several layers of clothing, and the warming charms he'd cast on the wooden structure had done little to ward off the bite of winter. He huddled deeper into his cloak and sipped from the steaming mug of tea he cradled in his numb hand as a distant church bell chimed, marking out midnight, and December 24th ticked over into December 25th.

Harry flicked his wand and with a whispered Expecto Patronum, a silver stag formed and looked at him expectantly, pawing the ground with its front hoof. 'Merry Christmas, Ron', he said to it, and at another gesture from his wand, the stag bounded off in the direction of Knockturn Alley, where Ron was sitting in a similar Auror station.

Putting down his mug, Harry got to his feet and stretched the kinks out of his back, then pulled on his heavy gloves in preparation for his hourly patrol of a mostly-deserted Diagon Alley.

When he'd come on shift at 6pm, Diagon Alley had been jam-packed full of wizards and witches intent on tracking down last-minute gifts for loved ones, and the atmosphere had been one of joyous anticipation.

Harry had been picked for the twilight patrol of Diagon Alley because of his familiar face; Ron had been assigned Knockturn Alley for the same reason. Robards said that their presence would make shoppers – still somewhat leery of large crowds, even six years after Voldemort's defeat – feel secure and safe, and Harry had to admit that people seemed to respond positively to seeing him repeatedly walking the length of Diagon Alley.

When the shops had closed at 8pm, leaving just residents making their way back and forth from the Leaky Cauldron, Harry had retreated to the Auror station per standard protocol. A thorough patrol of Diagon Alley took exactly twenty minutes, starting on the hour every hour, and Harry whiled away the time in between counting down the hours and minutes until 2am, when he could Apparate to the Burrow and crawl into a warm bed next to his warm wife for a few hours of sleep before the Christmas festivities started.

Hunching his shoulders against the cold and tugging his scarf up to cover his mouth and nose, Harry stepped out into the street, his wand clasped tightly in his hand.

A group of young women stumbled out of the Leaky, clinging giddily to each other as they giggled, and Harry nodded his acknowledgement of their 'Merry Christmas, Auror Potter!'. He waited until they were safely inside a house just down the road, then continued along Diagon Alley, using his wand to illuminate a multitude of hidden nooks and crannies.

Everything seemed in order; shops locked up tightly, no suspicious-looking people hanging around – it was quiet and still …

… except for the sweet, soft jingle of bells.

Frowning, Harry directed his wand in the direction of the noise, increasing the intensity of the beam of light.

A man was on the rooftop of an old grocers' that had been converted into a block of three flats. The man was plump and bearded and dressed in red, and was entirely too old to be climbing on a rooftop in the dead of night. And, regardless of age, he certainly shouldn't have been on a rooftop with a sack slung over his shoulder as he attempted to stuff himself into a chimney that was much too small to accept his rather large girth.

Harry turned on the spot, casting a sound-muffling charm at the same time, and Apparated onto the rooftop behind the man without so much as a pop. Intent on not startling the old man, he crept across the ridge, aiding his balance with a mild sticking spell, and stopped when he reached the chimney.

The man was apparently in the process of Transfiguring his body, as his lower legs were now in the chimney pot and he was wiggling his backside back and forth in an effort to squeeze his thighs down into the terracotta cylinder.

A quick bit of spellwork, and the burglar was immobilised and unable to Apparate. He was wedged firmly in the chimney, and Harry had to shove an extra burst of power into his levitation charm to pull the man out.

'I'm arresting you for attempted burglary,' Harry cautioned him. 'Anything you say may be used as evidence against you.' He sent his Patronus to Ron once more, letting him know that he'd made an arrest, and then gripped the man's arm. 'I'm going to side-along Apparate you to Auror HQ, where you will be held for questioning.'

'Harry Potter. Well, of course. That makes sense. You're quite possibly the only person in the world who can see me when you're not supposed to.' The man was rather cheerful despite the situation, and his round, red-cheeked face was jolly. 'Master of the Deathly Hallows and all that – it gives you a clarity of vision all others lack.'

Harry wasn't about to get into a debate with a crazy old man on a rooftop, so after sending Ron yet another Patronus to apprise him of the arrest, he tightened his grip on the man and span away into the squeezing darkness of Apparition.

They landed in the designated Apparition zone next to the booking desk at Auror Head-Quarters. Harry led his prisoner into a holding cell, binding him to one chair and then sitting on the other, staring intently at him.

'What's your name?' he asked, picking up the quill that had materialised in front of him and positioning the tip on the booking-in form.

'I have many names,' the old man said, 'depending on who I am speaking to.'

'Well, you're speaking to a very tired Harry Potter who wants to go home to bed, so pick a name,' Harry sighed.

'Nicholas. St. Nicholas.'

Harry had automatically written the name down before his brain registered what the man had said. Snorting, he scribbled out his spidery writing. 'Pull the other one, it's got jingle bells on. Name?'

'Père Noël.'

Harry raised an eyebrow. 'Try again.'

'Daidaín na Nollaig. Santa Klaus. Father Christmas.'

Frustrated, Harry shoved the parchment away from him and threw the quill down on top, ink splattering across the cream-coloured paper as he surged to his feet. 'I really don't have the patience for this, you know. It's Christmas, and I want to get this sorted and then go to bed, so can you please just give me your name?'

Just as the man opened his mouth again, the door burst open to admit a red-nosed Ron Weasley, his eyes wide and his mouth agape. 'Harry! Let him go!'

It was Harry's turn to gape as he stared at his insane brother-in-law. 'What do you mean, let him go? I found him trying to stuff himself down a chimney!'

'Let him go, because you bloody well arrested Father Christmas!' Ron all but shouted. 'Who's supposed to deliver the presents now? They're not going to deliver themselves, you know.'

The old man – Nicholas, for the sake of argument – beamed at Ron, his bright blue eyes twinkling and his apple-cheeks rosy. 'Did you see to my reindeer? They get rather upset when something like this happens. Dasher in particular – she's a bit sensitive, you see.'

Nodding, Ron pulled up a chair, gesturing for Harry to sit down again. 'I couldn't see them, but that little incident with Thestrals in fifth year left me used to dealing with invisible creatures. I left them some food and told them to stay put, and that I'd sort it out and have you back to them as soon as I could.'

'You've always been such a good boy, Ronald,' Nicholas told him, and Ron blushed, ducking his head. 'Don't be embarrassed. You earned your presents every year. I never had to keep anything back.'

Harry looked back and forth between the two of them, and then dropped his head into his hands in despair. 'The pair of you are both completely gone in the head,' he muttered.

He felt a touch on his shoulder, and looked up to find Nicholas standing next to him. 'You – how did you … you were bound to that chair!' he exclaimed, getting to his feet once more. 'What's going on?'

'You were four when you wrote to me for the first time,' Nicholas said. 'Well, it wasn't writing, not really – it was a drawing. You drew a picture of a mother and a father and a little boy, all smiling. Happy. You signed it "Harry", with a kiss at the end.' For the first time, his face was solemn, and the twinkle left his eyes. 'That was the first year I had to disappoint you,' he whispered. 'I couldn't give you the family you wanted.'

Harry's heart pounded fiercely in his chest. 'You work – well, for the post office or something. I know they collect all the letters addressed to Father Christmas. Someone must read them.'

'When you were six, you asked for a teddy bear. You wrote a letter – it was part of a lesson at school, and it was on bright green paper – and when you got home, you added a sentence to the end. You wrote, "A teddy bear would be my friend at bed time when I'm in my cupboard and stop me being scared." Nicholas paused when Ron made a choked sound, and he handed a handkerchief to the lanky redhead. 'When you were seven, you wanted a friend, someone who would play with you and make you laugh.' He smiled. 'It took me a while, but I eventually managed to get you a very good best friend.'

Ron sniffed loudly, and Harry tutted at him. 'This doesn't mean anything,' he snapped. 'Father Christmas doesn't exist.'

Nicholas ignored him and continued. 'At eight, you asked for a pet. Dudley had a hamster that you couldn't play with, but you had to clean out its cage. You said it'd be nice to have something that loved you.'

Harry stumbled backwards, away from the man. 'Stop it. You're … I don't know how you know this, but stop it.'

'You didn't write to me again after that – I imagine you stopped believing in me that year, after yet another disappointment. Every Christmas, I tried to deliver your presents, only to be thwarted by the wards around your Aunt and Uncle's house. So many presents, Harry – witches and wizards all over England tried to send you gifts.'

Shaking his head, Harry looked over at Ron. 'You're honestly telling me you believe him?' he demanded. 'This is mental.'

'He's Father Christmas, mate,' Ron shrugged. 'Just look at him.'

Harry snorted derisively. 'Father Christmas isn't real. You're twenty-four, Ron – you can't honestly believe that one man can deliver presents to every child in the world in one evening.'

'I deliver to adults, too, but it's not everyone in the world,' Nicholas interjected. 'Some don't celebrate Christmas at all, or have different traditions. And it's not all in one evening for me – to suggest that I could deliver to over 80 million homes in one night is ridiculous. I merely bend time. I'm about four months into this year's delivery schedule, with another three to go. It really is quite exhausting.'

'So all wizards and witches believe in Father Christmas, then?' Harry asked Ron. 'Grown men and women believe that a man in a red suit drops down their chimney once a year to deliver presents?'

'That's like asking if we all believe that we breathe oxygen. We know that Father Christmas delivers our presents,' Ron said. 'It's just how it is. People buy you presents, send them off to Father Christmas for safekeeping, and he delivers them to you on Christmas Eve. If you've been really good, you'll get a present that's just from him, and if you've been bad, he'll keep presents back until the next year.'

Harry rolled his eyes – he couldn't help himself. 'That's all well and good for Magical people – but what about Muggles? I know full well that Aunt Petunia used to keep Dudley's presents in the cupboard in their bedroom, because Dudley used to like to sneak in there and see what he was getting.'

Nicholas answered that one. 'Well, I deliver just one present to each Muggle child that has tried to be on their best behaviour throughout the year. Muggle adults – much like yourself – would struggle doing things the Magical way, so there's always a mystery parcel without the name of the sender on the tag – and it is from me.

'Needless to say, your cousin's name was never on the Nice list – even if it had been, I would have been unable to deliver it, much for the same reasons as I couldn't deliver yours.'

Harry looked at him, and suddenly began to laugh, uncontrollable chuckles spilling out of him. 'You … oh my God,' he wheezed, clutching at his stomach. 'Did George put you up to this?'

Nicholas ignored Harry's laughter, his hands locked across his round belly. 'Even though you stopped writing to me, you still thought about what you wanted for Christmas. Seven years ago, you sat at the mouth of a tent, listening to Hermione crying, and wanted Ronald to come back. You wanted that more than anything in the world.'

Harry opened his mouth to speak, but Nicholas talked over him. 'Three years ago, you bought an Engagement ring, and you hoped that Ginny would say yes when you asked her to be your wife. And this year, you want …'

'Don't …' Harry snapped. 'Just don't.' He snatched up the booking form and tore it half before incinerating it. As the last of the ashes settled onto the table, he shook his head. 'Just go. I'd struggle to make any charges stick anyway, so I'll save us the aggro and release you.'

Nicholas nodded to Ron, and then to Harry. 'Merry Christmas, boys, ' he said, before touching his finger to the side of his nose and disappearing into thin air.

Too tired to even argue that people couldn't Apparate out of the Interrogation room, Harry got wearily to his feet and looked at Ron. 'Come on, let's get to the Burrow. It's past our knocking off time.'

Ron followed him silently to the locker room to collect their things, and then they headed outside to the Apparition point. 'Harry …' he started, but Harry just closed his eyes and turned on the spot, intent on the Burrow.

Molly had left a light burning for them in the kitchen, its soft glow spilling through the window and across the yard in welcome.

Ron toed his boots off by the back door and hung up his robes before heading upstairs with a whispered 'G'night, mate, Merry Christmas.'

Once he was gone, Harry cast a Silencing Charm on the kettle and then put it on to boil, watching as steam began to pour out of the spout to hang in the cold air.

He didn't understand how Nicholas knew what he wanted for Christmas this year. Nobody knew – he hadn't even told Ginny, and she was part of it.

Harry was huddled over a cup of tea when he heard the stairs creak, and he looked up to see Molly coming down the stairs, her hair in disarray and her dressing gown wrapped tightly around her well-padded frame.

'Harry dear, why on earth are you still awake? It's after 3, you should be tucked up in bed – Father Christmas won't come if you're still awake!' She leaned down and pressed a kiss to his forehead, her hand cupping his cheek. 'What's wrong, sweetheart? You look a little down in the dumps.'

He shrugged, shockingly close to bursting into tears on his mother-in-law. 'I – well, I was just thinking about how different Christmas was for me growing up. Until I went to Hogwarts, it was always just another day, but with extra washing up for me to do.'

Molly's face hardened momentarily, and she opened her mouth as if to say something, and then visibly reconsidered. 'Well, that's behind you now,' she said, patting his face affectionately. 'Don't spare a thought for those awful people. We love you, and that's all that matters.'

He stood up and pulled her into a tight hug, breathing in the smell of vanilla and chocolate that made him feel like a child again. 'Thank you,' he said, as he released her and took a step back. 'I'm going to head off to bed now, I'll see you in the morning.'

'Goodnight, dear. Sleep tight.'

Harry smiled at her, and then made his way upstairs to the bathroom. Someone – probably Ginny – had set his pyjamas out and he pulled them on, grateful for the warming charms that had been placed on the soft flannel. A quick wee, a brush of his teeth, and he was ready for bed.

Tiptoeing along the landing, he quietly opened the door to Ginny's old room and slipped inside, shutting it behind him. Ginny was fast asleep, curled up on herself, and Teddy was nestled at her left, his camp-bed rumpled and abandoned, and his hair Weasley red.

After tucking in the blankets more securely around Teddy, Harry slipped beneath the covers. Ginny murmured in her sleep and shifted towards him, slipping a foot between his legs and sliding her hand across his chest.

Harry wrapped his arm around her waist and closed his eyes, pillowing his cheek against the top of her head, the flowery scent of her shampoo filling his nostrils.

He was asleep when the quiet, still Burrow echoed with the sound of bells.

'Harry! Ginny! Wake up, it's Christmas!'

Harry grunted into his pillow and pulled the quilt up over his head in an effort to hide from the shrill voice, but his efforts were to no avail.

With surprising ruthlessness for one so young, Teddy whipped the quilt sharply off the bed, exposing Harry and Ginny to the biting chill in the air.

'Teddy!' Ginny shrieked, scrabbling for a dressing gown. 'You little bugger, you wait 'til I get hold of you!'

Teddy howled with laughter as Ginny caught him around the waist and hauled him back on to the bed, relentlessly seeking out the ticklish spots at the backs of his knees.

Harry knuckled the sleep out of his eyes and fumbled for his glasses on the bedside table. 'Teddy, it's 6am,' he yawned, slumping back against the pillows. 'Let's go back to sleep for a bit.'

All the air left his lungs as Teddy launched himself onto his stomach. 'But it's Christmas!' Teddy said indignantly. 'There's presents, and Nanny Molly said she'll cook us all bacon butties for breakfast! Come on!'

Grumbling good naturedly, Harry pulled on his own dressing gown, and then slid his feet into his slippers. 'Alright then mate, let's get downstairs and see what you've got this year,' he said, letting Teddy pull him to his feet.

When they reached the landing, a hubbub of noise met them, and Victoire looked up at them from the foot of the stairs. 'Oh, Uncle Harry! Come and see!' she exclaimed, her eyes wide and sparkling. 'Father Christmas has been!'

Teddy let go of Harry's hand and bounded down the stairs to his little cohort, the two of them giggling like lunatics, with Harry and Ginny following at a more sedate pace, hand-in-hand.

They both stopped short at the sight that greeted them.

The living room was jam-packed full of presents. They were everywhere – the window ledge, stacked along the walls, on bookcases – some had even been enchanted to float just below the ceiling, bobbing overhead in a riot of ribbon and paper.

'They're all for you, Uncle Harry!' Victoire babbled, clapping her hands. 'Can I help?'

Harry managed to find an empty chair and sank down into it, looking uncomprehendingly at the presents. 'They're all for me?' he whispered. 'How?'

'I think Nicholas decided it was time you got all the presents you should have had all those years ago,' Ron said with a smile. 'Go on, Harry, pile in; our presents are under this lot, so we have to wait for you.'

In shock, Harry took the first parcel that was at hand and unwrapped it, carefully peeling the brittle tape away from the old, fragile paper. A bear tumbled out of the wrappings and into his lap. Its plush fur was a dark caramel, and its round, well stuffed belly was soft beneath his fingers.

He stroked the silky fur, and looked around at his family. 'Father Christmas is real?' he asked, and he almost winced at how incredibly young and in awe he sounded.

'Of course he is!' Molly scoffed. 'Now come on, dear, the little ones want to get started on their presents.'

Harry started unwrapping with a vengeance, encouraging Teddy, Victoire, Dominique and Lucy to join in. Before long, everybody was helping, and the floor was soon covered with all manner of toys and gifts, from a miniature Quidditch team to ornate robes, and a whole host of Muggle gifts which intrigued the children no end. Teddy was particularly enamoured of a toy Slimer, something Harry had long coveted as a boy, and wept with excitement when Harry said he could keep it. Andromeda protested that the slime would simply ruin the carpets, but she smiled at Harry over Teddy's bright blue head, and he knew that she secretly approved.

It took over an hour to unwrap all the presents addressed to Harry, and he was completely overwhelmed. He had evidence that people cared for him right in front of his nose. 'This is just … it's …'

Ginny took his hand, and pulled him out of the melee to stand just inside the doorway to the kitchen. 'I know,' she said quietly. 'It's a bit mad, isn't it?'

He nodded, watching their family laugh with one another as they began to hand the children their gifts. 'I can't believe Father Christmas is real,' he said. 'Why did you never tell me?'

She shrugged, slipping her arm around his waist. 'I didn't know I was supposed to,' she said. 'I didn't even realise that Muggles stop believing in him after a certain age.'

'I arrested him for breaking and entering last night – well, technically this morning, I guess,' Harry confessed. 'I saw this fat old bloke trying to get down a chimney and assumed that he was a burglar.'

Ginny shrieked with laughter. 'Oh, you didn't! I take it you let him go; otherwise we'd be looking at an empty living room right now.'

'Yeah, I let him go out of sheer frustration. I was convinced he'd done something to Ron, because Ron kept insisting that Father Christmas was real.' He paused for a moment. 'I don't know why I had so much trouble believing that Father Christmas exists, not after what I've seen in the Wizarding world. Father Christmas is actually one of the less unusual things, actually.'

She leaned against him, soft and warm at his side. 'You've not opened any of the presents from us yet, just all the old ones. Would you like one of mine now?' Her voice was quiet, and would have been lost in all the noise of a typical Weasley gathering if she hadn't been so close.

'Yeah, why not,' he said, suddenly realising that Ginny had probably been sending his gifts off to Father Christmas for years. 'Where is it?'

She took his hand in hers, and placed it on her stomach. 'I'm afraid you'll have to wait around seven months until your present actually arrives,' she smiled. 'But Merry Christmas. We're going to have a baby.'

Harry pulled her to him, holding her as close as he possibly could, and kissed her, laughing in delight as their lips met. 'A baby!' he crowed. 'I'm going to be a dad! You're going to be a mum!'

She broke away to grin at him. 'That's generally what happens when you have a baby, yes,' she teased. 'Come on, let's tell everyone. We might as well get the screaming over and done with.'

Harry found himself being tugged back into the living room, which resembled the aftermath of an explosion in a paper factory, and he just had to stop for a minute and take it all in.

Nicholas had known. He'd known that Harry's dearest wish was to become a father; he'd known that not too long ago, Harry had lain awake in bed and desperately hoped that the contraception potion would fail and he would have a child with Ginny.

'Harry, dear, there's one more present here for you,' Molly said, her voice oddly wavering. 'Is there something you both need to tell us?'

What was unmistakeably a Moses basket sat on the floor next to the tree, a ribbon tied around the wicker handles.

The gift-tag was a simple white rectangle of cardboard, covered in a curly, sprawling script. Dear Harry, it read. It has taken twenty long years, but this Christmas will see the realisation of what you have wanted since you were a child of four. This time next year, you will have a child – a family – of your own for me to bring presents to. Merry Christmas, dear boy. Love, Father Christmas.

Harry let go of the gift-tag and looked at the bright, expectant faces of his adopted family. 'We're having a baby,' he said simply, and he broke into a wide smile. 'We're having a baby!'

Every Weasley – by birth, marriage, or simply association – in the room attempted to hug the two of them all at the same time, and Harry found himself swept up in tears and back-slaps and embraces, and he returned all three in equal measure.

Ron caught him with a combination of all three, scooping him into a bearhug, slapping his back, and then dashing at the tears that ran down his freckled face. 'Harry, mate, this is just …'

'… brilliant,' Harry finished for him. 'Ron … he knew.'

Ron didn't need to ask who 'he' was. He grinned at Harry, and shrugged. 'I reckon you believe in him now, yeah?'

Returning the grin, Harry nodded. 'Yeah. Yeah, I do. I believe in Father Christmas.'

And when all the celebrating had died down a little, Harry found a quiet corner – easier said than done in a house full of seventeen people – and settled in to write a thank-you note to a man he hadn't believed in less than twelve hours previously.

Harry believed in magic – but now he believed in another sort of magic too, a magic that made him feel seven-years-old again and full of wonder.

He believed in Father Christmas.