The Leaky Cauldron was busy that night. Everybody seemed to have the same idea of relaxing after a long week of work, warming their fingers around mugs of Butterbeer, and drowning their sorrows with Firewhisky. Harry Potter and Ron Weasley were amongst the quiet gaggle of people, sitting in the corner with large goblets of mead.

In the year that had passed since their legendary defeat of Lord Voldemort, nothing had changed between the two of them, except that they didn't see each other quite as often as they would have liked. Harry was busy working in the Auror Office, and Ron, after completing his own training, had instead just started helping George to re-establish Weasleys' Wizard Wheezes. Tonight was the first night they'd seen each other in about a month, and they'd both been relishing the prospect.

"So, what's new, Harry? Defeated any dark wizards recently?" asked Ron, jokingly.

"Nah, decided to give up hunting down evil overlords, and delve into the mystical intricacies of cauldron bottoms instead."

Ron snorted into his mead. "I'm sure Percy would be honoured to have you following in his footsteps," he replied, with the utmost sincerity. "But, seriously, how're things? People got over the fact that you're Harry Potter yet?"

"Not really. Some of the witches who work in the Auror Administration Office are awful. They won't stop giggling every time my back is turned."

"Have you checked your back? Maybe you've sprouted green, hairy antlers and you haven't noticed."

"Ha ha. It's really irritating, actually. They hardly ever get any work done: they spend most of their time debating which 'Hogwarts Hero' they'd most like to date."

"Oh yeah? So, er, who features on their list, then?"

"Yes, Ron, you're on there. But don't get ahead of yourself - you've got a girlfriend, remember? Speaking of which, how is Hermione? Everything ok?"

"She's fine. Still trying to settle her parents down. I keep telling her they'll get better soon, but she won't believe me. She worries about them all the time."

"Well, y'know, they're her parents. Imagine if it was you," replied Harry, diplomatically. "Just remember to be sensitive like we talked about, yeah? But, anyway, what about your job, how's that going?"

"Oh, you know. Fine. At least George can face going back there now. I don't think the shop ever lost its popularity, though, even when it was closed. It's doing fantastically, but I can't help feeling that all that Auror training is being wasted."

"Yeah, but you get all the free jokes you want! And I hardly ever use my training skills. It's all office work, and with all those giggling girls in the office, sometimes I wish I had your job. Your life even. Then at least I wouldn't get recognised and simpered at everywhere."

"Are you kidding? For one thing, being an Auror is infinitely cooler than working in a joke shop, and for another, you're Harry Potter! You're the coolest person around. I wish I had your life."

There was a short silence as the two mulled over the conversation, then, as though someone had just flicked a switch, they sat up, both with the same mischievous look on their faces.

"Are you thinking what I'm thinking?" Harry asked, hesitantly.

"Maybe. What exactly are you thinking?"

"That maybe there is a way of swapping lives - just for a day, of course."

"If you're thinking Polyjuice Potion, then I am right with you," Ron said, smirking.

"Shall we do it?" asked Harry, his eyes lighting up in the way they always did when he was planning something against the rules. "We can't tell anyone."

"Do you even know how to make the potion?"

"Don't worry about that, it'll be easy."

"Alright then. So, in one month's time, you and I will become each other. Deal?"

"Deal."

They clunked their goblets together, sealing in that moment the set of unfortunate events that would shortly ensue.

*

"And you're sure you've done it right? I don't want to sprout a cat's tail like Hermione did," Ron asked, nervously.

"One hundred per cent positive. All we need now is the hair."

Harry yanked out a few strands of his thick black hair and sprinkled them into Ron's flask. The liquid turned the correct shade of gold, and he breathed a sigh of relief: it looked like the potion really had worked, and he hadn't been quite as sure as he'd said.

Ron added his own hair to Harry's flask, and the pair watched in interest as the potion turned a vibrant shade of orange, which strongly resembled Pumpkin juice. "Excellent, Chudley Cannon colours!" cried Ron.

They stood facing each other, holding their flasks tightly in their hands. "Remember," warned Harry, "we have to take it every hour. I don't want people to think I'm secretly ginger or something."

"Whatever. I know you cry yourself to sleep at night, wishing you had such luscious locks as mine."

"On the count of three. One, two, three!" The boys took large swigs from their flasks, and began to groan in pain as the transformations took place. When they finally straightened up, their eyes widened as they took in the sight before them.

"This is weird," gasped Ron.

"Seriously weird."

"We should swap clothes. It'll look odd if we're wearing clothes the wrong size."

"You're right. But quickly, you've got to be at the Ministry soon," replied Harry. They began to change, and when Harry was down to his underwear, he realised something. "Wait a minute! You don't have a tattoo of a pygmy puff? Ginny swore to me you did!"

"Ha ha," Ron grumbled, and Harry noticed that where Ron's ears usually went pink, his cheeks now turned rosy red.

"So, this is it?" Ron said, once they were fully clothed again.

"You know where to go, right?"

"Yep. You?"

"Yeah, course I do."

"Ok then. Um, bye!"

"See you this evening!"

The two of them turned on the spot, Disapparating. As Harry re-emerged outside the Leaky Cauldron, he wondered briefly whether this was actually a good idea or not; but he quickly dismissed the doubt, reasoning that it was only a bit of fun, and that not much could go wrong in a day, could it? He pushed open the door and entered the pub. "Morning, Mr Weasley," called Tom, over the bar.

Harry looked around, expecting to see George following him in, and then realised that Tom had been talking to him! "Oh, er, morning, Tom." He would have to remember who he was today.

He walked into the grubby courtyard behind the pub, and tapped the brick that would let him into the concealed street behind. Diagon Alley was finally back to its thriving self. The shops were filled with bright ornaments and trinkets, and people crowded the street and sat in little cafes, soaking up the morning sun.

Harry made his way through the bustle towards the now famous Weasleys' Wizard Wheezes. It was painted bright orange, and was so stuffed with merchandise that it looked like it might overflow any second. He grinned at the prospect of spending a whole day in there, and pushed open the door.

"Ron. You're very nearly late. I was just about to allocate you to be the Skiving Snackboxes demonstrator." It was George. Harry was surprised to see how pale he had become: an impressive feat for a ginger. He grinned at his new boss, but George didn't quite manage to grin back. His eyes remained emotionless, and Harry realised how hard it must be for him, to be stuck in a place surrounded by memories of his dead brother. Maybe that was why Ron wasn't so keen on working there.

"As you're just in time, I want you to man the New Merchandise desk. We've got three new jokes out this week: Exploding Ink, Slumber Solution and the White Winter Wonder-maker."

"Ok. What are those?"

"C'mon, Ron, we've been through this! Exploding Ink: friend's forgotten theirs? Lend them a bottle that'll make sure they never forget again. Ink explodes everywhere as soon as it touches the parchment. Slumber Solution: another addition to the Incredible Inks range. Dip in your Quill, suck on the end, and you will fall into a fifteen-minute sleep, and yet look like you're still wide awake. Finally, White Winter Wonder-maker: heat of summer? Fancy a snowball fight? This will cover your garden with a thick layer of real snow. Lasts one to two hours, depending on external temperature, and leaves no soggy slush. Ok?"

Harry was impressed. "Yeah, that's great, got it."

"Ok. We open in five. I want you ready in your robes by then." He tossed Harry a set of magenta robes which sparkled subtly, suggesting a strange starry sky. These were so going to clash with his hair.

When Harry emerged fully robed five minutes later, he could already see the queue forming outside the shop. Eager faces were pressed against the mullioned windows, trying to get a sneaky peak inside.

"Ready, Ron?" Harry started at the reminder of his identity, and nodded. "Alright, let's open up!"

It was pandemonium. Hordes of excited children pushed their way into the shop, exclaiming in delight at the legendary products they held in their hands. Harry could already hear parents issuing pointless warnings to their children. "Only ten minutes in here. Understand?" and, "no, you can't spend more than ten galleons!" He had a new admiration for Ron, working under these conditions.

As various children approached his stall with interest, he did his best to remember all the information George had given him, and was surprised how good it felt to see a child look beseechingly at their parents, and beg to buy the products.

"Good work, Ron," George said, "but let's see if you can beat your previous high score. Sell forty products before your lunch break, and you can have one for free." Well, now, here was a challenge. Did Harry have what it took to beat Ron? Of course I do, he thought, defiantly. Over the next hour, he sold harder than he had all morning, and he had just reached his thirty-seventh sell when George tapped him on the shoulder. "Too bad, Weasley. You didn't beat your personal best. But it was good going! Have an extra ten minutes off. I'll cover for you here."

"Brilliant! See you in a bit!"

Harry squeezed his way out of the shop and into the tiny staff room at the back. He breathed a sigh of relief, and appreciated Ron's hard work even more. Just as he was sitting down for lunch, he heard a movement behind him, and a small pair of hands covered his eyes.

"Guess who?"

His heart sunk. He recognised that girly, giggly, simpering voice. "Lavender?"

An ear-splitting peel of giggling pounded against his ear drums as Lavender Brown pranced around him, finally plonking herself down on his lap.

"W-what are you doing here?" he stammered.

"I came to see you, silly!" Harry was speechless. Ron wasn't cheating on Hermione, was he? No, that was stupid. He'd never do such a thing, and Harry would have found out somehow. "Didn't you get my owl?" continued Lavender, oblivious to Harry's obvious disgust. "I told you that I've decided to forgive you for going off with Hermione, as you were evidently under a lot of stress, what with You Know Who being back, so you can't have known what you were doing. So I'm ready for us to get back together!"

"But I'm - I - er - you-"

"Ron?" a small voice whispered, and Harry glanced up to find its origin. Hermione was standing at the door to the staff room, a look of devastation on her face.

*

Deep under the chewing gum-encrusted pavements of London, Ron's day was going much more smoothly. Harry had given him instructions on how to get to his office and the names of all the people he worked with. As Ron had entered the giant atrium that morning, he saw again the beautiful sapphire blue ceiling with the rotating golden runes, the masses of people Apparating in, and the new centrepiece: a delicate silver tree whose branches blossomed out in twirling tendrils, and whose dainty leaves were in fact made of a chain of hands all holding on to each other. A plaque underneath it read:

In memory of those who died fighting against Tom Riddle.
Those who unite stay the strongest.

He saw the names of every person who had died neatly engraved onto the trunk of the tree, and his heart tightened as he saw Fred's name carved next to those of Lupin and Tonks. He smiled sadly at the beauty of the memorial, and moved towards the rattling gold lifts.

On the second floor, Ron found a door with a plaque that read "Auror Office: Death Eater Detection Division," and walked in.

"Good morning, Harry!"

"Hi, Harry!"

"Hello, how are you, Harry?"

The babble of voices fought over each other for his attention, and Ron looked around, bemused, at all the attentive faces looking up at him.

"Are you hungry at all?" asked one, who Ron guessed to be Lavinia Bassiana, remembering Harry's vivid description of the girl whose beaky nose and bright yellow hair made her look like a canary. "I brought some chocolate muffins in, if you'd like one."

"Er, yeah, sure, that'd be great," replied Ron, never one to turn down an offer of food.

"I'll make you some coffee!" cried Parthenope Waterhurst, who, Ron had gathered, only ever made coffee.

"Cool, I'll, er, just be in my office."

"If there's anything you need, we're right here," called Tamora Andronica, the only girl who'd ever chosen Neville Longbottom as her 'Hogwarts Hero' date.

Ron sat back in Harry's office and grinned. How could Harry find these girls annoying? They seemed perfectly lovely. Maybe he'd ask for some cake while they were at it. Hermione was trying to encourage Ron to eat more healthily, but, he thought, technically it was Harry who would be eating all this food. He smiled lazily. He could get used to this.

After a few hours of hearing high-pitched shrieks of laughter from the other room, and having girls pop their heads around the door every two minutes "just to check on him," however, he began to understand Harry's irritation. At least Hermione never got starry-eyed around famous and important people. You'd never catch her giggling stupidly over the qualities of Quidditch players. She may be hard on him sometimes, but he knew it was just because she loved him and wanted him to do the best he could, and he suddenly realised how much more that meant to him than a bunch of girls quibbling over the benefits of ginger hair versus black hair.

At about half past twelve, Kinglsey Shacklebolt was shown into the room by a beaming Tamora, and for once the girls had gone quiet. The presence of the Minister for Magic seemed to awe them more than his - well, Harry's - did.

"Harry. I was wondering if you had that report for me on the most recent whereabouts of the remaining Death Eaters. I know we've only got a few left now, and I want to congratulate you for your excellent work."

"Oh, er, thanks."

"So, do you have the report?"

"Er, yeah, it's, er-" Harry had never mentioned a report! Ron looked wildly around, frantically hoping to spot it somewhere.

Just as he was abandoning hope, Tamora, who had been hovering in the doorway, cleared her throat. "I though you took it home last night to finish it off."

Ron had not thought he would ever feel gratitude towards this girl, but he had just been proven wrong. "Oh, yes, of course. I'm so sorry, Kingsley, I must have left it there. I'll just pop back and get it."

"No problem. I've got a meeting at two, so if you could have it on my desk before then, that'd be great."

"I'm on to it."

Kingsley left the room in a swirl of majestic robes, and Ron breathed a sigh of relief. "Thanks so much, Tamora."

"My pleasure, Harry. I there anything else you need?"

"No, no. I'll just go home and get the report. Shouldn't be too long."

He spun on the spot, picturing Harry's house in his mind, and opened his eyes again, to find himself standing right in front of it. He walked up the path and opened the door. He froze.

Sitting on the kitchen table, wearing nothing but a very revealing lacy bra and pants, was his little sister. "Harry, you're late. I've been waiting. You know what happens when you keep me waiting." Ron stared in horror at her lack of apparel. "You've been very naughty." She hopped down off the table and walked slowly towards him.

Ron had tried very hard over the past year to imagine that Harry and Ginny's relationship comprised only of holding hands. Apparently not. Before she could come any closer, Ron backed away, not even attempting to conceal the look of revulsion that he knew was decorating his face. "Put some clothes on this instant!" he cried.

"Oh, you're ordering me, are you?"

"NO! Seriously, woman, what is wrong with you? That's just disgusting!"

Ginny's alluring smile had vanished, and she looked hurt. "You didn't complain last time!"

"LAST TIME? You mean you've done this before?"

"What? Of course we have, how can you not remember?"

"Well, we don't talk about everything!"

"I still thought you'd remember stuff like that!" cried Ginny, evidently upset now. "What's wrong, why don't you like it anymore?"

Ron opened and closed his mouth, trying to think of anything to say that might improve the situation, as heaven knew it couldn't get any worse. Before he could say anything, however, he felt a strange prickling sensation along his hairline, and he realised too late that he'd forgotten to take his latest dose of Polyjuice Potion. Ginny's face changed from a look of hurt, to confusion, to shock, and finally anger, as she saw Ron standing before her, ears bright red, and a look of embarrassment on his face. "What the hell are you doing?" she hissed.

"I'm so sorry. I honestly didn't want this to happen."

"That - that is just sick, Ronald."

"NO! It's not what you're thinking! Harry and I just thought it would be funny to swap places for the day. I really, really didn't count on seeing you here!"

Ginny narrowed her eyes at him. "I think we'd better get Hermione."

Ron's stomach flipped over. This was not going to be good. Ginny strode over to the fireplace and threw some Floo powder into the empty grate. "Hermione, I need you." Green flames sprung up, and out climbed Hermione, followed closely by Harry, who still resembled Ron. They looked at each other, and both knew that they were in a lot of trouble. As Hermione straightened up, she caught sight of the real Ron, and stared. "It seems," said Ginny, "that these two had a marvellous idea. Unusual, I know. My darling brother," she gestured to Ron, "informs me that they took Polyjuice Potion so that they could swap places for the day."

Hermione looked alarmed and spun around to face Harry, whose hair had just that moment begun to darken. She watched with a mixture of anger and confusion as he began to transform back into himself, and then whirled around to face Ron. "So you've been in the Ministry all day?" she demanded. He nodded nervously, and she swivelled back round to Harry. "And you've been working in the joke shop?"

"Yes," he muttered, sheepishly.

Hermione said nothing for a couple of seconds, then, to everyone's surprise, began to laugh.

"It's not funny!" cried Ginny. "I - I hit on my own brother!" she whispered, flushing scarlet.

Hermione simply laughed harder. Harry and Ron stared at each other, uncomprehendingly. "You - you seriously thought you could pretend to be each other for a whole day?" she spluttered. "Oh, you are just so hopeless!"

The boys grinned at each other, nervously, but Harry stopped when he caught Ginny's eye. "You have a lot of explaining to do, Harry Potter," she snarled.

"Oh, don't worry about it, Ginny!" Hermione said, and then lowered her voice. "We'll get them back another time."

And, true enough, one month, two bottles of love potion and some awkward memories later, Harry and Ron found that the girls knew exactly how to get even.