A Way to "Deceive" Time?

Time flowed every moment.

But what exactly time was remained unsettled. Muggle science had its own definitions of time, and wizarding magic had its own understanding of it. Roger knew a little about both theories of time.

Though he did not fully understand the principles, Roger had some materials on practical applications.

Most of the books Professor McGonagall had lent Roger were theoretical studies and data reports. Among them was an internal Ministry of Magic research report published long ago.

Having gained absolute memory, Roger recreated the book with magic from memory.

Once you became proficient in Transfiguration, it was truly useful.

"Summary of Time Travel Experiments, 1899."

In the report, the author from the Department of Mysteries described in detail how none of those who had undertaken exceptionally long time travels in the past had survived.

After repeated testing, the researchers had determined that the safe limit for time travel was within a few hours.

Of course, that safety was only relative.

In truth, short trips were not without risk. It was simply that when the journey was brief enough, the effects you caused would not be excessively amplified by the chaotic butterfly effect of the long span of time. As long as you did not deliberately stir up trouble, the chance of suffering a backlash from the power of time would be reduced.

At the same time, the Department of Mysteries had verified through experiments that directly casting spacetime spells such as the Hour Reversal Charm was not the best choice for time travel.

The casting of a spell itself could be influenced by a wizard's stray thoughts. For ordinary little spells like the Levitation Charm, a minor error caused by a passing distraction would barely affect whether the spell was completed.

But spacetime spells were different. The slightest deviation could lead to a disaster a thousand miles away!

The best way to use such unstable magic was to seal spacetime spells within an enchanted object and make it into an alchemical item... Well, the result of their research back then had been the Time-Turner.

At the end of the report, the author mentioned the great disaster the Department of Mysteries had caused "that year."

In 1899, Eloise Mintable had been trapped in 1402 for five days. When she returned to the modern era, her body had aged by five centuries, suffering irreparable damage. She soon died at St Mungo's Hospital for Magical Maladies and Injuries.

Nor was that all. During those five days in the ancient past, she had severely interfered with everyone she encountered, drastically rewriting their lives. At least twenty-five of their descendants vanished from the modern era, becoming people who had "never been born."

And those were only the consequences observed by the Ministry of Magic. Who knew whether moving a wooden stake five centuries earlier had caused even more Muggles to silently "disappear," unnoticed by anyone?

There was nothing more after that in the report.

Because from 1899 onward, extended time travel had become a taboo of wizarding civilization. At least several hundred legal prohibitions had been specifically established for time travel, and the Department of Mysteries' related experiments had been permanently suspended. Even now, in 1991, nearly a century later, that remained the case.

...They had no choice but to stop. Even a top-tier wizard like Dumbledore could not withstand an attack from upstream on the timeline. What if someone had a sudden lapse in judgment, altered the past, and wrecked the entire world? Time was far too chaotic. Sometimes, merely moving a chair or breaking a horseshoe could completely change the worldline.

No one wanted to disappear. If anyone dared to play tricks with this, then they should not blame the strongest wizards across the globe—and the five great powers of the blue planet who learned of it—for coming to have a talk with them! The Ministry of Magic had always been in contact with the United Kingdom government, and other countries were much the same. The Statute of Secrecy was aimed at most people; the true upper echelons of Muggle society had always known wizards existed.

As he read the freshly printed report Roger had created and listened to Roger's explanation, Harry could not help turning back to look at him. "...By what you're saying, doesn't that mean going back in time to save my parents is completely impossible?!"

Seeing Harry's expression of Are you messing with me?, Roger smiled and shook his head. "No. Quite the opposite. The path to salvation is right in this report."

"We know that time travel itself accelerates the traveler's aging. So if one could achieve immortality, wouldn't that eliminate this side effect?"

"Changing established facts that have already occurred in the past can produce unpredictable consequences in the future. So don't change them. Instead, carry out your actions within a 'blind spot of time.'"

As he spoke, Roger gave an example.

"Say your heart stops right now and your body dies. That is an established fact that has already been observed. If it were rewritten, the 'worldline that continued based on your death' would be destroyed, and time would flow in another unknown direction."

"Then I could make use of a 'blind spot in spacetime.'"

"When my future self gains the ability to reconstruct a body for a dead person's soul, I will return to 'this moment,' deceive the perception of my present self, take away your soul, and resurrect you. At the same time, I will completely 'freeze' your body and consciousness inside a spatial rift I create with Space Magic, one that no one but me can open."

"I will return to the future, awaken your resurrected consciousness there, and take you out of the 'spacetime-sealed capsule' known as the spatial rift. Throughout the entire process, I will not alter even the slightest thing in the past, nor bring anything from the past into the future, reducing the backlash of spacetime to its minimum."

"Of course, if you were actually going to put this into practice, the problems you encountered would certainly be more numerous, more complicated, and more difficult than in the example I gave."

"But it is indeed one way of approaching the problem."

That was what Roger told Harry.

Harry's parents' corpses had long since decayed, and their souls were nowhere to be found. To resurrect them, time travel was indeed the least difficult of the many possible methods.

Harry's eyes lit up for a moment, but soon dimmed again.

He remembered that Voldemort had killed his parents. If he wanted to carry out the plan Roger described, he would at the very least need the ability to deceive Voldemort's senses and act right under his nose.

...Was that even possible? Not to mention the immortality he had no idea how to achieve.

"You don't need to worry about immortality. If I get results, I'll help you solve that... Of course, it won't be free."

"You only need to think about how you'll reverse time. It's difficult. You may have a long road ahead of you—perhaps one measured in centuries."

"But having some hope is better than having none, isn't it?"

Roger patted Harry on the shoulder. "In any case, you now roughly understand the difficulties involved. If you still want to take this path, come find me tomorrow. I'll make you a reading list."