"What would our mother say if she saw us now, Fred?"

"You know exactly what she'd say, George." His voice went up an octave in a rather accurate impression of the Weasley matriarch. "'If only you had put half this dedication in your studies, Merlin knows where you would be now!'"

"Working at the Ministry, I suppose."

The other pulled a face. "Who wants to be an upstanding citizen, anyway?"

"Not me, brother dearest. This is much more fun!"

"I don't know about you, but I'm not having any fun."

In truth, the place didn't look like the twins' flat at all. Gone were the garish packages of Skiving Snackboxes and the prototypes for new joke items that would erupt into funny noises at random (especially the ones for the additions to the Weasley's Wildfire Whiz-Bangs set, which kept exploding when they shouldn't), and in their place were tottering piles of books so complex you would get a headache just by looking at them. Discarded bits of parchment littered the floor, and a hastily conjured blackboard proudly displayed the results of the current research. In short, it looked like a place where Hermione Granger would thrive, and most certainly not like the home of the two professional troublemakers who had recently set up shop at 93, Diagon Alley one floor below.

"This was your idea, if I recall correctly."

"And I still think it's a good one. Just try to imagine the money this will rake in when it's done!"

"I am imagining it, thank you very much. But in the meantime..."

"... it means a lot of work, yes, I know. Patented Daydream Charms are proving a patented pain in the..."

"Think we're ready to try one yet?" George interrupted before the other could finish the sentence. He didn't miss their mother's constant reprimands about language, exactly, but they had to keep focused, or they'd never finish.

"Not really," said Fred. "But then, we'll never get anywhere if we don't start somewhere."

"Wise words, brother of mine," said George with mock solemnity. "On three?"

Fred nodded. "One..." To be honest, he looked as if he'd rather not be counting at all, but he wasn't a not-quite-graduated Gryffindor for nothing.

"Two..." George tried, without much success, to convince himself that his voice wasn't trembling.

"Three" they chorused finally, and spoke the incantation they'd spent the last few weeks meticulously planning down to the last syllable.

The room dissolved in a myriad of sparks, and when it reformed before their eyes, it didn't look the least bit like their house. In fact, it didn't look like anything they'd ever seen. It was circular, with a railing marking the limit between two separate zones, both of which would drive their father positively crazy with delight. Odd-looking consoles (that was the right word for them, wasn't it?) with blinking lights and more buttons than they'd know what to do with lined the walls, and in the middle, a chair that was obviously designed to look important faced... was that a window or what? It looked a little like a smaller version of the ceiling in the Great Hall at night, only the sky looked all kinds of wrong. There was some sort of structure floating among the stars, but no sane wizard would ever build a thing like that and risk violating the Statute of Secrecy. Not that its style looked much like something a wizard would ever want to create: they could make out 'K-7' on its outer walls, and if that was its name, well, it was the most dreadfully boring and unimaginative name ever invented. They could have done much better, for sure.

Worse yet, the Chair (with a capital C that was clearly deserved) was occupied, as were most of the other seats around them. The man in the centre pushed a button and the sound of a siren filled the air. This meant trouble.

The twins' hands automatically went to their pockets, but they were dismayed to find no wands there. Maybe this was a spell-induced daydream after all, but some daydream it was if the plot called for them to be wandless against a group of unknown people who outnumbered them and were getting ready to draw theirs... wait a minute, those didn't look like wands.

"Hey, are those firelegs?"

"It's firearms, George, Dad would have your hide."

"Who cares what they're called? As long as they're pointed at us, they're bad news."

"And they'll be even worse news if you two don't cooperate," said Mr Important Chair menacingly. He gestured sharply to someone behind them and they found themselves in the vice-like grip of two burly men in red shirts, each keeping their whatever-it-was uncomfortably close to their backs. Without a doubt, that was an excellent reason to cooperate, as he had put it. "Take them to the brig," he ordered. "I'll send someone shortly for the interrogation." He sighed softly and mumbled something that sounded like: "As if a priority one distress call weren't enough trouble for one day..."

The brig, it turned out, was a small cell with no door at all. As soon as the two men were out of earshot, Fred let out the laugh he'd been holding in.

"How do they expect to keep us here?" He marched up to the empty doorframe... and fell spectacularly backwards with a sound of something not unlike eckeltricity, or whatever it was called. "Ow!"

"Are you all right?"

"I think so..." Fred looked at the spot where he'd fallen as if it had personally offended him, but there it was, looking perfectly innocent and empty again. "It's only my pride that's wounded. They must have some sort of ward or something."

"Definitely not Muggles, then."

"But they looked like Muggles. Weird ones, but Muggles nonetheless. I didn't see a single robe or wand on any of them."

"Robes? As if. They looked like they were walking around in pyjamas to me."

"And they seem to know only three colours: red, yellow, and blue. These people need a lesson in taste."

"Somehow, I doubt they'll be willing to take any lessons from us. At least one of them must be a wizard, though."

"And how would you know? They didn't exactly stop to chat."

"Come on, Freddie. The one in blue with the weird ears. Didn't you see him?"

"Now that you mention it... Do you suppose he tried to Transfigure himself into something?"

George winced at the thought. "That's what you get for not listening in class."

Fred gasped dramatically. "I never thought I'd hear you say those words, brother. How could you?" he said in mock astonishment. "You sounded just like Percy."

That sobered him up. The memory of the great fight that had finally driven their older brother away was still as fresh as if it had happened the day before, and yet it had been several months since Percy decided he wanted nothing to do with any of his family, much less with two consummated mischief makers like the two of them.

"Okay, okay, I take it back. He didn't look half bad for a failed attempt, by the way. I've seen worse in our days."

"What do you think he was aiming for? We could try the same thing on purpose, it would make for a fine prank..."

"No idea, although with those ears, I wouldn't be surprised if he'd been thinking of a rabbit."

"A rabbit? Really? Think he read Babbitty Rabbitty and the Cackling Stump to his kids one too many times?"

"I'm afraid we'll never know."

They lapsed into silence for a few moments, but it simply wasn't in their nature to sit quietly and do nothing. Before long, Fred said: "Now what?"

"We wait, I guess. Their chief said something about an interrogation."

"Don't remind me. What are we going to tell them? 'Oh, hi, sorry to drop by unannounced, but we're wizards, you see, and one of our spells must have gone wrong...'"

"But if they're Muggles..."

"... that would break the Statute into a million tiny pieces. We might not have a choice, though."

"What do you mean?"

Fred gestured to the not-quite-door. "If they have that," he said, "they might have an equivalent of Veritaserum as well, and by the looks of them, they wouldn't be shy to use it if they did."

"I hate you when you're right."

"Believe me, I wish I were wrong on this."

And so they waited. And they waited. And they waited a little longer. But the interrogation never came. Something did come, or rather, an impressive quantity of little somethings, but it wasn't what they'd been expecting.

"Whoa, what are those?" said George when the first few of them ventured into the corridor beyond their cell.

"They look a little like those miniature Puffskeins we've been working on."

"Ours are better, though. They're a more interesting colour."

"True. When in doubt, go with purple."

"And pink for the girls, because let's face it, the Pygmy Puffs will mostly attract female customers."

"I can almost hear them. 'Oh, Mr Weasley, they're adorable!'"

"I suppose these little fellows are sort of cute too."

But George's words were destined to be proven wrong. The first time it happened, it was mildly interesting: one of the little balls of fur stopped dead in its tracks, ceased its rather relaxing purring, gave a loud, high-pitched squeak and started producing so many tiny copies of itself it was a wonder they could all have fit inside. All in all, a rather informative spectacle, if they had been in need of a reminder of the birds and the bees. But then it happened again and again. By the fifth time, the corridor began to get crowded, and the twins started making bets on how many more the next one would produce. By the tenth time or so, the pesky little things had to climb over one another if they hoped to get anywhere. At some point around the twentieth squeak, the creatures tried to invade their cell, which they fortunately couldn't do, because the same strange ward that kept them in also kept everything else out.

"You know, Gred, this could be an excellent business opportunity."

"Are you thinking what I'm thinking, Forge?"

Before they could finalize the details of their brand new plan, however, a shower of sparks whisked them away, and when the last of them were gone, the twins were back to their piles of unfinished notes.

Fred whistled softly. "That was some adventure!"

"At least we learnt something from it."

"Yeah, sure. How not to make Patented Daydream Charms."

"And there's something else, too."

Weeks later, at the grand opening of Weasley's Wizard Wheezes, a man beckoned George and asked: "Excuse me, I'm considering buying one of these for my daughter, but why are there two separate cages?"

"Just read the sign on that one, sir."

"'Mystery Puffs – Multiply the Mischief'," he read doubtfully. "What does that mean?"

"Let's just say, my dear sir," answered George, "that I recommend buying a regular one for your little girl, and one of these for your worst enemy."

There was a frighteningly competitive glint in the customer's eye at those words. "I think I'll do just that."

Two days after that, the man was back at the shop, lips quivering in an attempt to fight off a grin. This time, it was Fred who happened to have a moment to spare for him (the sales were going strong, thank Merlin, and he felt like he didn't even have time to breathe at rush hour).

"Good afternoon, sir. Can I help you?"

"I came to talk to you about a recent purchase of mine."

The corners of his mouth turned down. "Do you have any complaints?"

"Complaints? I came to thank you! Don't you remember... oh, you're not the same twin. Awfully sorry about that."

"Don't worry, sir. As we always say, our day isn't complete if it doesn't happen at least twice, and you're the second today. Anyway, what product are we talking about?"

"Your Mystery Puffs. I knew there was a reason behind the slogan, but I had no idea it was that accurate. Wimple's office was full of them in no time! And when he tried to Vanish them..."

"... they multiplied by ten, just like our fireworks. Can I interest you in some of those? The principle's the same, really..."

"No, thank you, I'm not one for explosions, that's Wimple's speciality... in fact, I thought he was going to explode! It was brilliant! Ordinarily, I'm not the world's biggest prankster, but doing it once in a while is good for the soul, let me tell you. He was swamped in those things! I'll never forget his face!"

Just then, George passed by and winked at him. "It's always nice to hear of our loyal customers' successful mischief making. May I recommend a Shield Hat in case poor Mr Wimple tries to take revenge? They're all the rage. Satisfaction guaranteed."

"Er... I can defend myself without it, I think. My daughter's very happy with the other Pygmy Puff, by the way. She named it Mrs Fuzz... she's perfectly convinced it's a girl, though it's hard to tell with all the fur, isn't it?"

"Must be the colour," said George.

"Oh, yes, she was ecstatic, pink is her favourite."

"Do tell her where Mrs Fuzz came from, we would love to see your daughter's face around here sometime," said Fred, smelling opportunity in the air.

"She makes enough trouble without your help, thank you very much." But his fond smile took the edge off the severity of his words. "I'll be back one of these days. I'm afraid I started a prank war that might involve the entire department, and I'll need ammunition."

"Spoken like a true mischief maker, sir," said George with an impish grin.

"We're looking forward to seeing you again."

As the man departed, George looked at the door that had just closed behind him and commented: "I think we have a new fan."

"You took the words right out of my mouth. Who knew reading up on the Gemino Curse could be so profitable?"

"And don't forget to thank our friends. Who knew inspiration could come from a bunch of crazy Muggles in pyjamas?"