Unerasure

Harry Potter was getting extremely frustrated searching the Hogwarts library for a book containing information he needed for his Potions assignment, which was due tomorrow. Suddenly, his fingers found the spine of a small book, which appeared to have been written by hand. A closer examination revealed the crests of Ravenclaw and Gryffindor on the book's spine and cover. Curiously, Harry opened the book and read the title (also handwritten): "The Book of Chaos: An Essential Companion for Troublemakers". Sitting down at a desk, Harry started to browse the book and to his surprise, he recognised some of the handwriting as belonging to James Potter, Sirius Black, and Remus Lupin. Surprisingly, there was nothing by Peter Pettigrew in the book, but on closer examination, the text written by Harry's father, godfather, and unofficial uncle revealed some truly amazing spells and potions. Sirius Black and James Potter had each written about a tenth of the Potions section of the book, and Remus Lupin had made numerous corrections and additions to various spells in other sections of the book.

Harry was so engrossed in the book that he didn't notice Ron Weasley arriving.

"Found anything for that assignment of Snape's yet?" asked Ron.

"Not yet, but I did find this book," replied Harry. "This is really interesting. Some of the inventions in this book are incredible. Take a look at this spell: just write your destination time and place on a piece of paper, cast the spell, and you're there."

"Bloody hell, Harry, that's fantastic. Just think of what we could do with that spell. Too bad we didn't have that book when we had to do History of Magic. That would have been really useful. We could have gone back in time and checked whatever it was that Binns was talking about."

"There is a slight problem with the time-travel spell, though: your senses get scrambled for two minutes for every year you go backwards in time. It's only one minute per year if you go forwards"

Ron looked a bit disappointed at this news.

"Still, there are heaps of unsolved crimes that the Ministry of Magic would love to finally solve," the redhead pointed out.

"Yeah, I know what you mean, Ron. Dad told me about a mysterious Avada Kedavra death in 1924. No matching wand for the spell's signature was ever found, until my wands were made."

"You have a couple of brother wands, don't you, Harry?" asked Ron.

"Exactly. I've always wondered about that killing, especially considering that the wand which was used wasn't made until 1936."

"So, think you can do what the Aurors can't?"

"I believe I can," replied Harry with dead certainty.

The next Saturday saw Harry outfitted with transfigured clothing appropriate for the 1920s and virtually every supply he could think of. Ron was there to see him off on his trip through time.

"You know, Harry, I'm really impressed that you're doing this to solve a crime. I'll bet that the Ministry will give you an award for solving it," said Ron.

"Either that, or they'll throw me in Azkaban for illegal use of time-travel. Mum does say that access to time-turners is highly restricted, so imagine what the Ministry will think of the use of a spell like the one I'm about to use."

"Good luck, mate. Here's to solving the case."

"I'll drink to that."

Harry and Ron made a toast with a couple of Butterbeers they'd been saving for a special occasion. They figured that something as important as solving such a mysterious crime warranted it. After downing their Butterbeers, Harry cast the spell for time-travel and vanished into thin air.

Remus was certainly right about the sensory scrambling. Harry was just glad that he'd calculated how much time he'd need for the scrambling to wear off and adjusted his arrival time accordingly. At 16:58, by Harry's watch, the last of the scrambling finally wore off and Harry was able to get a decent look at his surroundings.

The late afternoon light illuminated a well-tended garden with plenty of bushes to hide in. While taking in his surroundings, a burst of coloured static appeared behind some bushes and resolved itself into two people holding onto a piece of paper. One of them looked like a younger version of the man who was to be murdered in a matter of hours, while the other one looked like a battle-scarred version of Harry himself.

'They must have used the time-travel spell as well!' he realised, almost gasping and giving away his location. Only now did Harry realise that these people must be the ones responsible for the murder and that by being in the past, he had the opportunity to change the future.

While Harry's doppelganger and the Tom Riddle look-alike were clearly stuck with their senses scrambled, Harry headed for the house.

Knocking on the door, he was met by Tom Riddle, looking just like a coloured version of the archival photograph of the man.

"What do you want?" demanded Riddle.

"Sir, I have reason to believe that there will be an attempt on your life tonight."

"What? You'd better come inside before someone overhears us talking." Tom Riddle roughly pulled Harry into the house and quickly shut the door.

Harry quickly put up a silencing charm around himself and Tom. "Mr Riddle, this may sound hard to believe, but please hear me out."

"Very well, I'll hear you out, but I can't make any promises about believing you."

"I'm from the future. How I came back in time isn't important, but what is important is that you are a statistic in the unsolved murders in my time. I think I might know how you were murdered, and right now, I'm offering to try and save your life."

"Who's planning on killing me and when?"

"Someone who looks uncannily like a younger version of you, possibly a future descendant, and a very different version of myself. I think they're trying to change history."

"And you want to try and save me to stop them?"

"Yes. I think the history I know is not the correct version, anyway. If I stop them from killing you, history will go back to its normal track."

"Well, do what you have to do."

"Okay, here's the plan..."

Harry made his way out of the Riddle house disguised as Tom Riddle and entered the car. Taking the key and starting it he began to drive off when suddenly his world was engulfed in green light and he found the car passing through him.

"I must be dead," Harry said to himself.

Looking around, he could see his doppelgänger and the Tom Riddle lookalike standing up behind the bushes and grinning triumphantly. Clearly they thought that they had succeeded in killing Tom Riddle. Suddenly, there was a burst of light off to one side, and Harry looked to see the car bursting into flames. When he looked back at the other time-travellers, Harry saw his double writing on a piece of paper, which he then tore in two.

Harry's double handed one piece to Tom Riddle's double and cast a spell and the lookalike vanished into thin air. Seconds later, the duplicate Harry repeated the process on himself and vanished, too.

Harry turned his eyes to looking at his own hands, which were growing ever-more transparent by the second. The last thing he saw before disappearing from existence altogether was Tom Riddle rushing out of the house towards the wrecked car.

"Good luck for the future, Tom," said Harry, and winked out of existence.

Due to Harry's sacrifice in saving Tom Riddle Senior, Voldemort was born and caused his reign of terror in the 1970s, killing many people in the process. Yet, as a side-effect of the First Voldemort War, some people were born who never existed before Harry created his nemesis. One such person was Hermione Granger, who was never born in the original timeline, but became one of Harry's best friends due in part to Voldemort's actions in their first year at Hogwarts. When the Second Voldemort War began in 1995, the corrupt Ministry of Magic went into denial before being forced to admit Voldemort's return.

Over the course of events, Harry lost his parents to Voldemort, his godfather to Death Eaters, and his mentor, Albus Dumbledore, to a man he believed to be a traitor, but wouldn't find out the truth about until a year later.