Disclaimer: They're not mine and they never will be :-(

Three cheers for Ms Rowling!!!

Warning!! This chapter is long and dry and you might have to read it a couple of times to get the theory. I promise it does make sense.

The headmaster nodded to himself as he noted Fred's presence, a slight smile gracing his features.

Then he was all business.

"We have much to discuss."

…………………………………………………………………

"We do indeed," Sirius said under his breath as Dumbledore took a seat.

"Where do we begin?" James queried.

"The beginning," said Dumbledore, "I believe the beginning is always a very good place to start." He chuckled at some private joke. "Especially since Mr. Weasley has been so kind as to grace us with his presence. I believe we might start with the original timeline. What can you tell us Fred? How have events been different in this timeline from the first reality you remember?"

If anyone was surprised at how informed Dumbledore appeared to be no one showed it. Obviously Dumbledore had seen the connection between Fred's illness and the time traveling incident eighteen years earlier.

Fred hesitated only a millisecond before reeling off everything he could think of, "My Dad was still alive, so was Lupin," James winced, "Harry was born, so was my little sister Ginny. Neville Longbottom was still alive. We didn't live a Grimmald place, at least my family didn't, we were still at the burrow. Ron was different. People liked him a bit. Even that Hermione girl he doesn't like. Sirius was wanted for the murder of twelve muggles and the betrayal of the Potters to You Know Who. The Potters were James and Lily, they were married….and dead. But You Know Who disappeared for years. The war didn't happen like it did here. It was over. You Know Who had only recently returned when George and I got our hands on the time turner."

Fred has said all of this quite quickly and factually, not daring to look at Sirius or James, who had of course already known most of this.

Dumbledore's brows sank toward his nose. He opened his mouth as if to ask for clarification on some fact or another, but quickly closed it again. To Fred it appeared as though Dumbledore were trying to sort through the large amount of information that had just been uploaded onto him.

"Voldemort returned?" he eventually asked. "From where? Where did Voldemort disappear to?"

Fred opened his mouth to answer then stopped. Paused to think. "No one knows really. It was because of Harry though. He tried to kill Harry but couldn't. It was like the spell just kind of backfired and no one ever really knew why. You Know Who disappeared after that. Harry was famous. They called him "The boy who lived.""

"The boy who lived." Dumbledore repeated the words slowly. "Yet he was never allowed to live in this reality."

"Right,"

"And James and Lily…." Dumbledore turned his gaze to James.

"Dead," James confirmed. "That's what Harry said too. The night they disappeared. He said he was an orphan." His gaze was on the floor. Sirius was giving him a sympathetic look.

"Ahh," said Dumbledore, nodding slightly, "I see."

"So how did that change things?" asked Fred, "One of you must have done something differently. When do we go back and fix it?"

Sirius whipped his head around and fixed an angry glare on the teen. "Fix it?! You call letting Lily and James die 'fixing it'. What makes your precious reality any better than this one? The only difference I can see is that the victims are different. Voldemort is still out there. You said yourself he'd managed to return to power even before you went back in time."

"He was gone for fourteen years!" Fred yelled, "There weren't as many dead piled up. Things were bad but not like this!"

"You're only saying that because Arthur's dead," Sirius returned harshly.

Fred turned White.

"Enough!" Dumbledore thundered with enough force to shake the portraits around his office. They scattered out of their frames in fright. "Enough," Dumbledore said again.

James raised his head to face the headmaster, "Is it possible to change it back?" he asked quietly.

"You can't mean.." Sirius began, but cut himself off at a harsh glance from James.

"That depends on your meaning James," Dumbledore replied solemnly. "Can we undo what has been done? No. No one can ever do that."

"But we did," Fred argued, "Harry and I, we changed everything."

"No," said James firmly, "It was me who changed it. It was a mistake and now I need to change it back, just tell me how Professor."

"James," said Sirius softly, "I want Remus and the rest of them to be alive as much as you do, but you can't just give up, you can't…"

"What do you mean it can't be undone?" Fred interrupted, directing the question to Dumbledore.

Dumbledore raised a white brow at Sirius.

"All ears," Sirius said, meaning he wouldn't interrupt.

"Have any of you done any serious research on the topic of time travel?" Dumbledore asked.

"Quite a bit after Fred and Harry disappeared," Sirius answered. "Particularly Remus and me. We wanted to know why they had gone. What would happen to the timeline."

Dumbledore leaned forward in his chair, "Did you happen to discover any volumes on the topic of multiple timelines? The branching effect?"

Sirius looked confused. "It was mentioned briefly in a few chapters. Considered irrelevant by most. We only live in the one timeline no matter how many others exist."

"Yes, yes," Dumbledore muttered, "That was the theory back in the seventies when you undertook that research. You haven't read anything more recent on the topic? The works of Alderdash Squerk?"

Sirius shook his head.

"I never wanted to know about it," James admitted darkly.

"So what's the current theory then?" asked Fred, giving James a look of utter disdain.

"The branching theory Sirius, what do you remember?" Dumbledore prompted.

Sirius shook his head and raised one hand up to his temple, "Branching theory," he said, "alright. For every choice that is made, for every possibility that exists, there also exists a dimension in which those possibilities are realities. As time moves forward more and more realities or dimensions are created. Like the branches of a tree, although the branches do not end. They extend and multiply infinitely. No being can exist in more than one dimension at a time. Beings multiply as dimensions multiply."

James stared at his friend, clearly impressed. "You remembered that from research you did with Remus in the seventies?"

Sirius shrugged, "What can I say? Mind like a steel trap."

"But what has that got to do with time travel?" asked Fred, "We only time travel in the one dimension right? The one timeline."

"We are coming to that now," Dumbledore said, "What time travel theorists have come to believe in modern times is that no timeline, no one dimension can ever really be changed. Once it is created it is created and what is done cannot be undone."

"I don't quite follow," said James, "Our timeline was changed. Harry's birth was undone, it all changed."

"No," said Dumbledore, "I don't believe it did."

"You mean they're all still alive somewhere?" Sirius asked sharply, "Remus, Arthur, Harry. They still exist?"

"In another dimension," Dumbledore confirmed.

"Another branch of the tree," Fred murmured, catching on.

"A branch of the tree which, I believe, ended last night with Fred and Harry's trip back in time."

"Ended?" James queried, "I thought they couldn't end. Isn't that what Sirius said before?"

Sirius nodded, his gaze fixed on Dumbledore.

"Mmm." Dumbledore inclined his head toward Sirius, "Indeed that was the theory eighteen years ago. Modern research provides us with a different theory which I will explain: If change is instigated by time travelers to their own histories a branch may end. Time travelers cannot change the history of their own branch, or shorten it. They must have their histories, their pasts, their personalities in order to become time travelers in the first place, and changing that history would create an unthinkable paradox. In all cases of time travel, timelines will come to a halt, or pause if you will, once the time traveling spell has been cast. The timeline resumes when the time travelers either catch up with the time they left behind, or return to it via a spell, but only if nothing in their own histories has been altered, or, as was the plan with Harry and Fred, the alterations are looped upon themselves with a potion designed to create small temporal folds. If the alterations are not looped, the timeline will remain paused for an eternity. It will end. A new timeline will stem from the original branch at the point from which the alterations were made."

Fred, Sirius and James all stared blankly.

Dumbledore sighed and conjured a blackboard and chalk.

"Here," he said. "This is Harry and Fred's original timeline." He drew a long white line across the board and received understanding nods from his three pupils. "From the end of this timeline Fred and Harry went back in time to this point here." He tapped the board at a point on the line then labeled it "1978". "For the few days that Harry and Fred were with us nothing significant was altered. Nothing that could not have been looped with the potion they were to drink. Not until the exact instant they disappeared from their beds that night. Was that when you made your decision James?"

"It was," said James with no particular inflection.

"Of course," Dumbledore turned back to the board, "In any case it was at that point that a new timeline was created. A new branch of the tree in which Harry was not born and Harry and Fred did not travel back in time." He drew a chalk line to represent the new branch. "When the new branch was created Fred and Harry were immediately absorbed back into their own natural timeline as they no longer belonged in this one. No longer belonged in a timeline which would never provide them with the opportunity to travel back in time."

"Okay," said Fred, "So I was absorbed back into the original timeline. Why am I now here in this one?"

'Because your own timeline paused Fred. Do you see? When you and Harry traveled back in time your timeline ended. Once you had gone back in time and changed history, the only reason for your own timeline to exist any longer was to create the set of circumstances that would lead to you and Harry having that accident with the time turner. To prevent paradox. Do you understand? Now that you have traveled back in time, that timeline has no need to continue, and you as the time traveler have managed to converge with the Fred Weasley of this timeline who never time traveled at all. Do you see?"

Fred frowned. He felt that could almost see, but all this philosophical discussion was hurting his head somewhat.

"So it's like two Fred's from different timelines in the same body?" asked Sirius.

"I believe so,' Dumbledore nodded gravely. "Although this the only practical case I've ever heard of. All theory on this subject has been, until now, just that, theory."

"You mean no one's ever altered time enough to have two people in the same body before?" asked James.

"Oh I would assume they have," said Dumbledore with a slight smile, "but think of how particular our circumstances are. Time travelers who have found themselves in Fred's position in the past may simply have died before they had a chance to take the mind expansion potion. Or perhaps they were simply not believed when they claimed to possess knowledge of another version of history. Whatever the reason Fred's is the only practical experience I have heard of that supports the branching theory as I have explained to you here today."

"So all the people who weren't supposed to die still exist in the first timeline. They weren't just erased? Can we save them?" asked James, impatient now with the academic discussion. "Remus and the others, can we save them?"

All eyes turned to Dumbledore.

He shook his head slowly.

"We cannot erase that which has been done," he said carefully, but there was an expectant tone to his voice, as though he was waiting for his pupils to arrive at some conclusion without his spelling it out for them.

"So they are gone," said Fred, "There's nothing we can do?"

"We can create a new timeline," said James, "a new branch."

"But we can't change it back," said Sirius, "It will never be quite the way it was for Fred the first time around. Maybe we can save them all. James and Lily too."

"No," said James with finality, "I have to die."

It was as though he had hammered the last nail into his own coffin.

It was almost clichéd.

No one knew quite what to say.

…………………………………………………………………

Don't say I didn't warn you!

Thanks for the lovely reviews as always!

Ness - He's not entirely dead. Although watching you go ballistic might be amusing.

Lacy - Less character stuff in this one unfortunately, but they'll be back and in anguish in chapter 28, don't you worry.

Faerie Lover - Hope it was worth the wait.

Duskrider Q - Hmm. I hate it when the good guys all agree. Where's the fun in that?

Blacknight - The prophesy didn't save Harry. It just predicted that Voldemort would mark one of them his equal and then one of them would knock the other off. Lily saved Harry.

Leena - Sama - Nice to see someone following my hints.

Templa - Thanks as always. I loved writing the twins. They're fantastic in the books. Hoped you liked the philosophy in this one.

Parrot - Fred and George are happy making.

Jeanne2 - Whiskey is relieved to remain on the cliff.

Summer rain... - Sorry, I know it's getting messier every time I update.:-p

Tapdancing Parakeet - Wow! That was impressive. But who says the prphesy won't still come to pass somehow?

P D Yerf - I hate those stories too. Hmm, maybe it should have been a sequel. Right now I'm kind of viewing it as act two of a three act story though.

Riley - Can I work where you work?

Hello? Mary - Happy Birthday (I know it was a while ago by now) My 22nd is on Friday.

1000chpsdlicious - Blasphemy backatcha.

The next one will be a bit more drama-ey. See you all then.