Disclaimer: I do not own Harry Potter. JK Rowling, her publishers, and Warner Brothers own Harry Potter.

A/N: This fic will be lighter than Darkness Visible. Chapters will be longer, but the fic itself will be shorter. It will be focused on the twins, with the Marauders and Snape as secondary characters.

Chapter 1: Sorting Things Out

- October 30, 1994 –

"I got the sneezewort!" George shouted excitedly, entering the sixth-year boys' dormitory.

Fred cheered. "Knew you could do it!" he said, beaming at his twin. "Any trouble getting in?"

"Nah," George said. He took out his wand and began undoing the transfigurations he and Fred had made to disguise him. "No one questioned seeing a Slytherin in the dungeons, or heading to Snape's office." He gestured at the "borrowed" uniform he was wearing. The house elves had been only too happy to help two of their favorite students, provided that they promise to return the uniform before laundry day.

"Told you," Fred said smugly. "Now all we need to do is add it, and then keep the potion stable while it matures. Then pour this little beauty on the age line –"

" – and then no more age line," George finished happily, handing Fred the liberated ingredient. After measuring carefully, he added it to the simmering potion.

The door to their dormitory burst open, and Lee Jordan ran in, breathing heavily. "Hey," he panted, "you'll never believe what happened! Cormac just tried to snog Katie!"

"What?" George whipped around to stare at Lee. "You're kidding!"

"No! Honest to goodness," Lee said.

"What'd she do?" Fred asked, laughing.

"Well –"

The potion exploded.

"Good evening, gentlemen," a familiar voice said. Fred opened his eyes. He was lying in a bed in the Hogwarts Infirmary. George lay on the bed across from him, blinking blearily. Headmaster Dumbledore stood at the other side of the room, looking unusually grave.

"What – what happened?" Fred asked. "Where's Lee?"

"I was rather hoping you could tell me," Dumbledore replied. "I admit, I was not expecting to see two unfamiliar students in Gryffindor tower two days before the start of term. Nor do I believe I know anyone with that name."

"Unfamiliar?" George asked, incredulous. "He's the quidditch commentator. How can you not know him? Or us?"

Dumbledore frowned. "The quidditch commentator is Miss Elsbeth Goldstein. And I am afraid that I have not had the pleasure of meeting either of you young men before now."

Fred started to laugh. "Good one, sir," he said, chuckling. "You almost had us believing you."

"But given the number of times –"

"– we've been sent to your office –"

"– we know you'd never forget us!"

Dumbledore shook his head. "I admit, you two bear an uncanny resemblance to the Prewett twins, who graduated several years ago and were frequent visitors to my office. However, I have already taken the liberty of consulting with them, and they assure me that they have nothing to do with your mysterious appearance. For once, I am inclined to believe them."

Fred and George exchanged worried glances. Uncles Fabian and Gideon Prewett had died only a few days before they had been born. They certainly had not graduated several years ago. Twenty years ago, maybe. Not several. "Headmaster, um, what year is it?" George asked.

Dumbledore's eyebrows rose. "You claim to be from another time?" he asked.

The twins shrugged in unison. "That would depend on what year it is," Fred said.

"It's 1994 for us," George added.

The headmaster frowned. "I see," he said. "Would you mind if I confirmed that?" he asked.

Fred shrugged. "Sure."

Dumbledore stared into his eyes. Fred suddenly felt an urge to blink, but found that he could not. After what felt like several minutes, Dumbledore turned aside. "My apologies, my boys. It appears that you have indeed travelled through time. The current date is August 30, 1976."

Fred and George choked. They had not even been born yet. Percy had barely been born. He would only be eight days old. Fred shook his head in disbelief. He could not imagine Percy the Prat as a squalling infant. He glanced at George, and then they turned back to the headmaster. "How can we –"

" – get back?"

Dumbledore shrugged, blue eyes twinkling. "Time does not like to be meddled with, and often finds a way to restore equilibrium on its own. I suspect – although, alas, I cannot be certain – that your visit to us here will only be a temporary one. I shall need to run some tests to be positive, but I would imagine that your predicament should resolve itself."

Well, that was a relief, at least. Not that being back in the pas would necessarily be such a bad thing. Fred was fairly certain that he and George could remember enough about what happened in 1976 to earn a decent amount of gold. Ludo Bagman got his start as beater for the Wimbourne Wasps that year, didn't he? It would only be fair that they earn something from his success, given how he cheated them after the World Cup.

Fred suddenly felt guilty. There were better things – far better things – to use their knowledge on. Mum's brothers. "Sir, could you make sure that the Prewett twins stay away from Diagon Alley on March 30, 1978?" George nodded vigorously.

Dumbledore's blue eyes sparkled, but his tone was somber as he said, "Your thoughts do you credit, my boy, but the past cannot – should not – be changed. Terrible things happen to wizards who meddle with time." He sighed, looking suddenly old and weary. "Terrible things," he repeated. "Often, things worse than that which the wizard tried to prevent. I am certain you know many things that I would like to know, especially given the current political climate." You-Know-Who, Fred thought. "But time has a way of seeking vengeance. If, for instance, I acted to save your uncles – yes, I deduced the relation – time might instead redirect itself to find another target, a target even closer to your hearts."

"You've tried changing things before," George accused.

Dumbledore nodded. "And lost far more the second time. I would not see anyone else fall into that trap."

Fred gulped. He glanced again at George, who nodded. They would keep their knowledge a secret. Pranks were one thing. Playing with people's lives was something else entirely.

Dumbledore clapped his hands, breaking the somber silence that had fallen. "Well, now that that is settled, we will need some identities for you two gentlemen."

"I'm G-" Fred began, but Dumbledore held up a hand, interrupting him.

"I do not wish to know. Indeed, I think it extremely dangerous if I do know, given that I am, apparently, still the headmaster when you, ah, disappeared. The less information I have, the less ability I shall have to affect the timeline, even unintentionally. Furthermore, the less others know, the safer we shall be.

"Now, I do believe that you," he nodded at Fred, "would make an excellent Feodor Vassilyev." Nodding at George, he continued, "Whereas you seem more like a Gustav." He sighed. "My first instinct is to isolate you from others for the integrity of our timeline."

"No!" Fred shouted, appalled.

"You can't do that!" George agreed.

Dumbledore raised a quieting hand. "As I said, that is my first instinct. However, I agree that – given that I cannot be certain how long you shall remain trapped in this time – extended confinement would only be cruel. Although this is against my better judgment, you do appear to be students and this is a school. I will allow you both to attend classes, but I wish to impress upon you the importance of not trying to change events. Even if – " His voice faltered momentarily, and then he continued, "Even if the life of someone you know and love is threatened." He sighed. "Be warned that I will not hesitate to reconsider should I feel that you are a danger to the timeline."

Who did Dumbledore lose? Fred wondered.

"Yes, sir," George said seriously.

Dumbledore smiled. "Excellent. In that case, which classes are you taking? I would recommend Divination for the pair of you – something that I do not often say – as it will provide a ready excuse should you accidentally refer to something that has yet to take place. And which year are you in?"

"Sixth," Fred said. "And we're taking Potions, Charms, Transfiguration, and Defense."

"And Divination," George added.

"Excellent," Dumbledore said again. "I'll ensure that both of you have the necessary supplies." He paused. "And, I think, it might be wise to alter your appearance somewhat. You do both greatly resemble the Prewett twins."

- September 1, 1976 –

Albus beamed and clapped as each of the new first year students was Sorted. Finally, "Yeats, Sinead" was sent to Ravenclaw. He rose from his throne-like chair at the center of the staff table. "And now, I am delighted to announce the arrival of two transfer students, Feodor and Gustav Vassilyev. They will be joining the sixth year class. I hope each and every one of you will make them feel welcome. Professor McGonagall, if you would please place the Sorting Hat on them?"

Feodor stepped forward first, grinning and bowing at each of the various tables. Even with non-descript brown hair, thicker eyebrows, and sharper cheekbones, Albus could see the Prewett twins in every line of his movement.

I wonder if I could . . . . Albus forced himself away from that train of thought. All those years ago, he had gone back a few hours to try and save Aberforth's legs, lost when Ariana's accidental magic had lashed out. He had succeeded, but a mere hour later, Aberforth and Gellert had gotten into their terrible argument, and Ariana – poor, sweet, innocent Ariana – had ended up dead. Never again would he risk meddling with time.

"GRYFFINDOR!" the Hat shouted after barely a few seconds on Feodor's head. The young man removed the Hat with a flourish, bowing deeply to Minerva as he did so, and then jauntily made his way to the laughing, applauding Gryffindor table.

Minerva called Gustav's name. He blew kisses to the crowd as he approached the Hat. Minerva closed her eyes as if fortifying herself for a long year, and then placed it on his head.

There was a long, long pause. At last, the Hat shouted, "SLYTHERIN!" Albus sighed slightly in relief. The Hat had initially argued against automatically re-Sorting the two boys in their original Houses, saying that people could change over time. Although Albus certainly agreed, he worried that placing the two of them together would risk letting more information about the future slip out than if they were separated. In his experience, people were more likely to discuss sensitive information in the supposed privacy of the dorms than elsewhere in the castle, and Albus was concerned that their roommates might overhear something that they should not. Besides, judging by their uniforms, they had been Sorted into different Houses once before.

From the Gryffindor table, Feodor nearly fell off the bench in shock. "What?" he shouted, sounding horrified. Albus felt a sinking feeling in his stomach. Was Gustav not a Slytherin before? But he was wearing a Slytherin uniform!

Gustav handed the Hat back to Minerva, and then stuck his tongue out at his twin and winked. He stuck his nose in the air in an over-the-top parody of snootiness and strolled lazily to the Slytherin table.

"Well, you're about as easy to Sort as it gets, just like your twin. Gryffindor through and through, aren't you? You were one before, and you're one still," the Sorting Hat said in George's mind.

"Good to know," George thought. "Why haven't you called it out, then?"

"Well, I would normally. But the headmaster really wants to separate you two. He's worried you'll talk about your little time travel adventure in the dorms, where prying ears will hear. Maybe you will, maybe you won't. But I thought I'd give you the option at least. You can go to Gryffindor, which is where you belong, personality-wise. Or I can put you in Slytherin, which is where he thinks you should go."

"What?" George asked, horrified. How could Dumbledore possibly think I belong there? He's supposed to know everything!

"No one knows everything, not even sentient hats that can read every thought in your head." George flushed slightly. He had not meant to direct that last thought to the Hat. "And besides, you were wearing a Slytherin uniform when you showed up here. It's not like he was pulling the idea out of nowhere. Now, you – and your twin – are, admittedly, clever and ambitious – that joke shop idea is a good dream, very fitting – but, frankly, you are so overwhelmingly a Gryffindor that I wouldn't normally even consider offering you an alternative if the headmaster hadn't insisted.

"So, what'll it be? I'm giving you the choice because I was told to, but it's always the student's choice. Not their family's, and not the school's."

George considered for a moment, and then smiled. It would be the greatest prank ever.

"SLYTHERIN!" the Hat shouted to the Hall. George caught Fred's eye as he removed the Hat from his head. His twin looked flabbergasted. George stuck his tongue out at him and winked. Fred blinked, and then smiled back with a small nod before feigning absolute horror.

Oh, yes. This will be fun.

Fred could not believe the amazing prank George had managed to pull. He wished his twin had consulted him before doing it. He would have liked a chance to scope out the Slytherin dorms. Even going to Ravenclaw or Hufflepuff might be fun, given that it was just going to be a temporary arrangement. Maybe it was a spur of the moment thing. Wish I'd thought of it. He shrugged. Oh, well.

Dumbledore said a few words, and then food appeared on the House tables. Fred grabbed a bit of everything. Raising his glass of pumpkin juice, he toasted George, who returned the salute with a grin.

"So, Feodor, was it?" a pretty, dark-haired girl next to him asked.

"My fame precedes me!" he exclaimed, putting a hand to his forehead in mock surprise. A few of the students nearby chuckled.

"Ooh, he's a prankster if ever I saw one!" a handsome teenager with thick, wavy black hair called from down the table. "Don't you think so, Prongs?"

Prongs? Fred turned his head to stare at the boy who had spoken. He looked vaguely familiar, but Fred could not place where. The boy next to him, though . . . . Fred nearly spat out his pumpkin juice in surprise. The boy looked almost exactly like Harry Potter. The boy was older, and there was no lightning-shaped scar, and his eyes were hazel, not green. But even so . . . . And he was Prongs? Fred wondered if Harry knew that his father was one of the great, infamous Marauders.

Wait, is that Professor Lupin sitting across from them? It certainly looked like a younger version of their former Defense professor. Much younger. Wow, the years were really bad to him. He looked a lot less shabby, too. Even though his robes were clearly second-hand, they were no worse than what Fred and George normally wore. If Dumbledore could get us new supplies when we showed up, why couldn't he get some for Lupin, too? He frowned. Or us, back in our own time? Ron even had to use a second-hand wand 'til Dad won the Prophet's sweepstakes last year.

"You know, Padfoot, I think you might be right," Harry's lookalike said. That other one is Padfoot! Fred thought excitedly. George'll eat his hat, missing this! He grinned at Fred. "James Potter, pleased to meet you."

A round of introductions followed. Fred tried not to react too badly when Sirius Black introduced himself. The other boy seemed to notice, though, and grimaced. "Ignore what you heard about my family," he spat. "I'm nothing like them."

"The white sheep of the Black family," James added, putting a friendly arm around his friend.

He's going to betray you someday. He desperately wanted to warn James, wanted to say something so that Harry would not have to grow up without his parents. He nearly did, but stopped himself. Time doesn't like to be meddled with, Dumbledore said. What if I say something, and Harry ends up dying instead? Hating himself, Fred forced a smile. "Right," he said. "Sorry. It's just the name, you know?"

Sirius snorted. "Yeah, trust me, I know. But I'm not my family. I'm not." He smiled grimly. "Besides, it's not like I'm the only one with family in Slytherin."

"Yeah, what's up with that?" James asked. "A twin in with those snakes?"

"The good twin," Sirius said, gesturing theatrically at Fred. "And the evil twin." He glared at the Slytherin table.

"Ge-Gustav's not evil," Fred snapped. Not like you are, Black.

"Then what's he doing in Slytherin?" a pudgy boy asked. From the introductions earlier, Fred thought his name was Peter Pettigrew. Looking at him, though, it was hard to reconcile the small, mousy boy with the knowledge that he would grow up to become the war hero who earned a posthumous Order of Merlin for his heroic – and fatal – confrontation with the treacherous Black.

Fred could see the friendliness of the surrounding students vanishing. He remembered that this was 1976, and that You-Know-Who was at the height of his power. Sorting into Slytherin was a one-way ticket to becoming a Death Eater. Eleven-year-olds might be forgiven for not knowing that when they Sorted, maybe, but someone transferring into Hogwarts as a sixth year would certainly know. Oh, George, what have you gotten yourself into?

Fred shrugged. "Well, you saw how long he was under the Hat," he said. "It didn't want to place him there, I reckon. But twins can get away with a lot, you know. A bit strange if we don't hang out. Worked it all out with Dumbledore before term started," He tapped his nose meaningfully.

Peter looked confused, but Lupin – no, Remus, call him Remus – choked, his eyes wide. "What is it, Moony?" James asked.

Professor Lupin was Moony? Always knew he was awesome.

"He's a spy?" Remus whispered.

"But that's really dangerous!" an absolutely stunning girl with auburn hair and a prefect badge said. She had not introduced herself yet, but with a pang, Fred recognized her from Harry's photo album. Lily Potter.

"Can't say one way or the other," Fred replied, but he winked.

The atmosphere at the Gryffindor table lightened considerably after that.

At the Slytherin table, George was relieved to see Fred grin and offer him a toast. He hadn't really expected his twin to begrudge him for his prank. Die of jealousy, sure, but not actually be upset. It was good to get confirmation, though.

Across from him, a blond boy with a shiny prefect badge extended a hand. "Evan Rosier," he said.

"Gustav Vassilyev," George replied, shaking the proffered hand.

"Yes," Rosier said wryly. "I know. Transfer students are not exactly common, you realize. Nor are twins who are Sorted into rival Houses. I trust that won't be a problem?"

"No problem at all," George said.

"Vassilyev's a Russian name, isn't it?" the girl next to Rosier asked. "Is that where you're from?"

"No," George said, glad he and Fred had worked out their cover story with Dumbledore beforehand. It would have been awkward if they gave contradictory answers. "Our family was Russian originally, but we've lived in Britain for a few generations now."

"But they were wizards, at least?" a large, muscular boy asked aggressively.

"I'm in Slytherin, aren't I?" George asked.

The muscular boy chuckled approvingly. "Glad to hear it. There are some," he glared down the table, but George could not tell who it was directed at, "who think they can tarnish the good name of our House with their inferior blood." Joining the House of soon-to-be Death Eaters might not have been the best idea I ever had, George realized.

"Don't bother, Mulciber. He's skipped the feast again," someone called.

The muscular boy – Mulciber? – snorted. "Good riddance. The stench would put me off my food."

Rosier raised a hand. "Now, Mulciber, be fair. The scarecrow's gotten better since he got his accent fixed." Around them, a few students shuddered as if reminded of something horrific. George was feeling very curious about the identity of the student. A non-pureblood in Slytherin. Might be someone worth knowing.

"He's still a disgrace," Mulciber insisted. He paused, and then added, "And he's insane." George was disliking Mulciber more and more. The student he was complaining about seemed like he could be interesting, though.

"Well, yes," Rosier agreed good-naturedly. "I'll give you that. But he's also one of ours, even if you don't like him much. I don't like him much." He shrugged. "Still, he's useful if you can get over the lamentable aesthetic issues. And he's brilliant. But if you want to give him grief, go right ahead. Just give me warning so I can be somewhere else when he tears your face off, alright?"

Yes, George definitely liked the sound of this guy. He hoped it didn't turn out to be someone horrible, like Malfoy or anyone equally despicable. Nah, he thought, Malfoy's a pureblood. Besides, didn't Professor Moody say that the head of the auror office had been a Slytherin? Scrim-something. Scrimjaw? Maybe it's him. He was about to ask for the name of the student, when Dumbledore rose from the staff table.

"And now that you are all fed and watered, I have a few start of term notices. First, Mister Filch has asked me to inform you that Pinkerton's Permanent Paint and Fizzbang's Firecrackers are no longer allowed on the grounds. You are welcome to consult the full list of banned goods in his office. I am told that it now consists of over 150 separate items." Dumbledore's mustache twitched.

"Finally, I would like to inform students, new and old, that the forest on the grounds is strictly forbidden. I trust that, with this reminder, there shall be no unfortunately misunderstandings this year."

"Sure thing, Professor!" a handsome, black-haired boy shouted from the Gryffindor table. The other students laughed.

"Idiot," murmured Rosier, shaking his head.

"Thank you for your agreement, Mister Black," Dumbledore said, eyes twinkling. Black? Not Sirius Black! He was a Gryffindor? "And now, off to bed!" Dumbledore said. "Prefects, if you'll lead the way?"

Rosier stood. "Follow me, Vassilyev," he said. Louder, he called out, "First years, follow me!"

He and the other prefects led the Slytherin students to the dungeons. They passed the potions classroom, and George suddenly realized that he had not seen Snape up at the staff table. Maybe he's not a professor yet? he guessed. He hoped not. It would be fantastic to be shot of the greasy git, even if only until he and Fred returned to their own time.

"Pineapple," Rosier said upon reaching a stone wall. It opened to reveal a grand room illuminated by greenish light. A window on the far end of the room looked out at the lake. Two merfolk swam past, and one of the first years gasped. Mulciber chuckled nastily, earning a glare from Rosier. Once everyone was inside, the opening in the stone wall closed.

"Password changes every fortnight," Rosier said. "Do not share it with anyone outside Slytherin. I don't care if your girlfriend or baby brother wants to visit. You do not share the password. Got it?" There were nods from the assembled students. "Great. Professor Slughorn, our Head of House, will be at breakfast tomorrow with your schedules." Ha! Sounds like no Snape for potions! "Now off to bed, the lot of you. First years, through here." He turned to Mulciber. "Show Vassilyev our dorm, won't you?"

Mulciber grunted but led George down the hall and through an open door, followed by two other boys. There were six beds in the room, and the two boys whose names George did not yet know each made their ways towards ones near the middle of the room. "That's mine," Mulciber said, pointing to the nearest bed. "Avery's, Wilkes'." The other two boys each nodded as Mulciber said their names. "That one's yours, I guess," Mulciber continued, pointing to a bed next to the trunk that Dumbledore had provided for him. "Rosier's, and," he wrinkled his nose in distaste, "Snape's."

George choked. Snape? Professor Snape was going to be his roommate? Mulciber smirked, misinterpreting George's reaction. "I know. Filthy half-blood." He spat on the floor in the direction of Snape's bed. Wait, Snape's a half-blood?

"Where is Snape, anyway?" Avery asked. "If he skipped the feast, shouldn't he be here?"

Wilkes shrugged, yawning. "Showers, probably. You know what he's like at the start of term." At George's confused look, he added, "When Mulciber says 'filthy half-blood,' he means filthy. Snape's probably spent the whole feast in the shower, getting the grime off."

"Wish he could get the grease off, too," Avery muttered.

George's thoughts were reeling. The Slytherins don't like Snape? They always seemed to like him. Could that much have changed in eighteen years?

The answer, apparently, was yes. George had just finished brushing his teeth and changing into his pajamas when what could only be the teenaged Severus Snape came into the dorm. They boy had the same distinctive, oversized hooked nose and limp black hair, which hung in curtains to hide most of his sallow face. But he moved with none of the adult's confidence. His rounded shoulders were hunched forward, and he kept his eyes down and averted from his dorm mates. His clothes were not the accustomed billowing black robes, but a threadbare school uniform that looked to have been poorly modified to fit someone taller and thinner than its original owner.

"Snape," Rosier said in greeting. "We missed you at the feast."

Mulciber grunted. Snape turned his head in his direction, but did not meet the muscular boy's eyes. This is the fearsome potions master? He turned back towards Rosier and shrugged. "Wasn't hungry."

A heavy silence filled the room. "Right," Rosier said at last. "Well, glad you got a chance to clean up. Since you missed the feast, I guess you haven't heard about our new transfer students. This here," he nodded towards George, "is Gustav Vassilyev. He'll be joining out year."

"Pleased to meet you," George said, extending a hand towards Snape. And isn't this surreal?

Snape's eyes flicked towards George's outstretched hand warily, as if he was afraid that this was somehow a trap. Apparently satisfied, he took it. George barely hid a flicker of surprise at the evident callouses on the long, delicate-looking fingers. "Severus Snape," he said. It was same deep, rich voice that George remembered. "Transfer students, you said? Where are the others?"

"My twin brother's in Gryffindor."

"My condolences," Snape said. The other boys in the room chuckled. George frowned.

"Well, I'm off to bed," George said, clapping Snape on the back. Merlin, wait until I tell this to Fred! To his surprise, Snape winced and staggered slightly at the contact. Turning back to his bed, George caught a brief flicker of disapproval on Rosier's face.

A/N:

Long author's note. Sorry!

Dumbledore used legilimency just enough to confirm the twins' time travel story. He is actively trying not to learn too much about the future, for exactly the reasons he explains in this chapter. This does not necessarily contradict his actions in PoA, since he already knew that Buckbeak miraculously escaped before suggesting that Harry and Hermione rescue innocent lives. He was ensuring the continuity of the timeline he remembered, not trying to change the past.

Fred and George only know what their characters knew as of the night before the champions' selection in GoF. They therefore know about the Marauders' Map and that Remus is a werewolf. However, they do not know about the Shrieking Shack incident, that Peter Pettigrew framed Sirius Black for the betrayal of the Potters, or that Snape was a Death Eater-turned-spy (in GoF, Sirius told Harry that despite hanging around future Death Eaters in school, Snape had never even been accused of being one himself. This suggests it was not common knowledge).

Feodor Vassilyev was the husband of the woman credited to have borne the most children in history. No, Dumbledore did not mean this as a shot at Weasley fecundity (especially since, at this point, Molly and Arthur only have three children). But "Vassilyev" sounds vaguely like "Weasley," and from what the twins let slip, Dumbledore does know that they are related to that family. He simply figures that similar-sounding names are easier to remember.

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