Horizontal Spacetime

Ten years later, Earth.

Headquarters of the United Nations Human Army;

The night before Operation Morning Star.

“Doctor.”

Hmm? The man known as Doctor looked up from a pile of documents. His previously dull expression softened with a faint, weary smile upon seeing his visitor.

“General, still not planning to rest at this hour?”

The doctor smiled.

“Just call me Bai Ci…” Bai Ci tilted his lips wryly, as if his relationship with this man—now hailed as the Light of Humanity, Dr. Lumiér—was far more complicated than mere titles suggested.

“Tomorrow is the eve of Operation Morning Star. Shouldn’t the General be conserving strength? The Extinction Species won’t grant you a second chance to sleep.”

“Does humanity even have a next time?”

At that, the doctor fell silent.

Operation Morning Star—the largest and final global offensive against the Extinction Species in human history.

Bai Ci would lead the assault as the vanguard commander targeting the Seventh Nest of the Extinction Species. An undeniably daunting mission.

“Humans are truly incredible creatures,” Bai Ci mused, lighting a cigarette with casual ease. “Ten years ago, on that day, I was so terrified by the sight of an Extinction Species I couldn’t even move.”

“And yet look at you now,” he added. “All thanks to you, Doctor.”

Bai Ci’s praise wasn’t flattery. The man before him, Dr. Lumiér, had—just five months after the initial invasion—successfully developed weapons capable of standing against the Extinction Species. By reverse-engineering the T-element from their bodies and combining it with top-secret mecha technology from Amerika, he created the Armored Mechs.

Even so, humanity still clung to survival by a thread.

Now, on the eve of Morning Star, eighty percent of Earth’s landmass had already fallen.

This operation would commit every last resource—every weapon, every mech, every soldier—in one final holy war against annihilation.

“General… have you ever heard of the concept of parallel worlds?”

The doctor poured himself a cup of coffee and continued:

“The Extinction Species… I suspect they may not originate from our universe at all.”

“They’re lifeforms projected onto Earth from another world, through some kind of dimensional echo. That’s why their elemental composition doesn’t exist in our reality.”

Bai Ci understood—this wasn’t baseless speculation. During humanity’s first regional counteroffensive, they’d discovered something terrifying: no matter how thoroughly they wiped out the Extinction Species in an area using T-element fusion rounds, the creatures would inevitably return—sometimes in greater numbers.

“Maybe,” Bai Ci shrugged, not taking the idea too seriously. With no guarantee he’d even see the sun two days from now, pondering metaphysics felt beyond his duty.

“If parallel worlds do exist… would I be the hero or the villain there?”

“In that case,” the doctor said, his smile fading into solemn certainty, “you’d definitely be the hero.”

You are the one who will save this planet.

“Tomorrow, you’ll command the Pacific Sky-Island battlefield. Do you know why?” the doctor asked.

Bai Ci shook his head. There were few officers better than him, but certainly not none. Given the stakes, the role should’ve gone to someone more seasoned—not someone who still appeared relatively young.

“Because it has to be you.”

Has to be me?

“Come with me.” The doctor turned and led Bai Ci down to the deepest level of the military base.

SSS-class top secret clearance. Bai Ci knew this was a lab accessible only to the doctor and the Supreme Commander.

He followed without a word.

The doctor walked slowly toward a massive cultivation tank and said, “Inside here lies the T-element, extracted directly from the Extinction Species.”

You already know, don’t you, that the Armored Mechs—the most effective weapons we have against the Extinction Species—are built upon this very substance.

Bai Ci nodded. As a mech pilot, he was intimately familiar with what the doctor described.

“But what you may not know,” the doctor continued, “is that the concentration of T-element varies across each mech.”

Bai Ci frowned. As a soldier, he’d never dealt with technical specifics. His job was simply to fight.

Seeing Bai Ci’s confusion, the doctor pressed on:

“For an individual with exceptional physical conditioning and rigorous training, linking with a mech containing twenty percent T-element is possible. You’re aware, of course, of how many pilots fail the fusion process—how many explode from within during synchronization.”

“Only those with extraordinary talent—or some latent force within their bodies—can surpass this limit and merge with mechs of higher T-element concentration… and thus, greater power.”

“And you, General Bai Ci.” The doctor paused.

“The T-element ratio in your Tian Shu mech is…”

“100%.”

“Do you understand what that means? Before you attempted fusion with Tian Shu, that unit had already claimed the lives of hundreds of pilots—soldiers capable of merging with 70%-concentration mechs.”

“You are the only person who has ever successfully synchronized with it.”

A strange, almost manic light flickered in the doctor’s eyes.

Bai Ci remained silent. He knew the doctor wasn’t finished.

“Do you grasp the significance?” The doctor paused again.

“It means that at the moment of synchronization, you temporarily possess 100% of the same T-element that constitutes the Extinction Species.”

“For that brief instant, you become, in essence, one of them.”

“And therefore… you may also gain their ability to project between parallel worlds.”

Right now, most people believe the Armored Mechs are merely weapons. But their true purpose… is to serve as devices for interdimensional travel.

And you, General Bai Ci…

You are the only individual recognized and accepted by the perfect jump device—Tian Shu.”

“So tomorrow’s Operation Morning Star… is your initiation ritual.”

“What’s the success rate?”

Bai Ci absorbed the revelation quickly, but the doctor’s words raised too many questions.

He couldn’t believe the doctor would gamble the fate of humanity on such an unproven theory.

“Unknown. It could be 100%. It could be zero.”

“Are you prepared to become humanity’s greatest criminal, Doctor?” Bai Ci asked coldly.

He had trained for this mission for far too long.

And now the doctor was telling him that Morning Star wasn’t a battle plan—it was a reckless experiment.

“Isn’t science itself built on hypotheses first, then proven through action?” the doctor replied with a smile.

Sacrificing all of humanity as experimental collateral…

“As long as parallel worlds exist, the success rate of Morning Star is 100%, General.”

In the dim lab, the cultivation tank pulsed with eerie light. The doctor locked eyes with Bai Ci.

“If the Extinction Species truly arrive via dimensional jumps, then there must be a ‘door’ connecting our world to theirs. Currently, that world continuously funnels information—and organisms—through this door into Earth.”

“Unfortunately, we’ve never been able to locate it. It might be hidden within one of the nests… or perhaps not on Earth at all. Maybe on the Moon. Or another planet.”

“So what’s your point?” Bai Ci listened quietly, the doctor’s theory sounding absurd—yet coming from the man who had already saved humanity, it demanded consideration.

“Therefore, I don’t intend to find that door.”

“I plan to use overwhelming force to smash open a new one.”

“Even then, the new door will only remain open for an instant. But in that moment… we can reverse the flow of gravity in our world.”

“Like water always flowing downhill, our world exists downstream from theirs—hence the endless stream of Extinction Species.”

“But if someone cups water in their palms and throws it upstream…”

“For just a moment, that water rises above its origin.”

“And Operation Morning Star is about creating that hand—the force that hurls humanity’s defiance upstream.”

“Tomorrow, as the largest coordinated strike against the Extinction Species, we will deploy every T-element weapon, every T-missile, and every Armored Mech to bombard occupied zones.”

“In the resulting storm of hellish energy, according to my calculations, the Pacific Sky-Island battlefield—where you will stand—will become the convergence point of all residual T-energy.”

“At that precise instant, a rift reversing space-time will open. Due to the law of energy conservation, the world of the Extinction Species will absorb back the energy it lost.”

“And since you pilot a mech composed of 100% T-element—identical to their biology—you will be pulled along with them.”

“You will be drawn, with perfect accuracy, into the Extinction Species’ original dimension.”

“Do you understand now, General? The true purpose of Operation Morning Star… is to open the gateway—for you to jump worlds.”

The doctor spoke with calm precision.

“…Is it really necessary for me to go?” Bai Ci finally asked, beginning to grasp the full scope. “Wouldn’t sending the Extinction Species back be enough? Isn’t my presence redundant?”

“General, remember—we’re only forcing open a new door and pushing them back.”

“The original door remains open. It will continue pouring Extinction Species into our world.”

“Humanity no longer has the resources to launch a second Morning Star within the next fifty years.”

“We’ve run out of time and capital to search for the door on Earth.”

“That’s why you must go to their world—and shut down the link between our dimensions.”

Me? Just one insignificant human? Bai Ci wasn’t afraid of going to that world. He was afraid of bearing the weight of all humanity’s hopes. He understood exactly what this meant.

Are you kidding me? I need a mech just to face the Extinction Species…

Are you kidding me? To place the survival of the entire species on my shoulders?

Find the door? I can’t. Even the doctor can’t… I…

No, General. The doctor interrupted, as if anticipating Bai Ci’s refusal.

He slowly approached another massive vessel, speaking with profound intent:

“Have you ever heard theories about fate?”

Some people seem naturally luckier than others. Most dismiss it as coincidence.

But in truth, these individuals possess a heightened ability to subconsciously seize the branch of the future they desire.

The doctor continued: “Say you decide to eat KFC for lunch. Unbeknownst to you, Store A used spoiled ingredients today—eating there carries an 80% chance of severe food poisoning.”

“You usually go to Store A. Logically, with no knowledge of the risk, you’d follow habit and walk in.”

“But your innate grasp of fate triggers a thought: ‘Store B’s new menu item looks good too.’ So you go there instead, enjoy a delicious meal, and avoid three days of agony.”

“This ability—what ordinary people call intuition, or sixth sense—is, in reality, a person’s capacity to steer their own destiny.”

“This phenomenon,” the doctor went on, “has long been proven by me. In humans, it correlates directly with the percentage of T-element fusion.”

“In other words, the higher one’s T-element compatibility, the greater their control over fate.”

“This is one of my core research areas.”

“Our world’s timeline and causality are strict—perfectly coherent from beginning to end.”

“You carry the unique cause: the ability to host a 100% T-element mech. Therefore, a corresponding effect must exist in your future.”

“Conversely, if a certain effect exists in the future, then its cause must have occurred in the past.”

“Only when, in the latter half of the timeline—your future—you unconsciously select the path leading to your destined outcome, does the first half—the present—reveal your ability to control fate.”

“And that ability, made manifest, is your 100% T-element fusion rate.”

“I’ve seen your future,” the doctor said softly. “Through countless unconscious choices aligned with fate, you arrive at what you believe to be the one and only solution.”

“So let me ask you one thing,”

The doctor pushed up his thick glasses, lenses nearly as wide as the specimen tanks.

“What fate… is it that you truly wish to find?”

“To save humanity…?”

Bai Ci answered, uncertain.

But was that really what he wanted?

An image flashed in his mind—the girl who had faded in his arms ten years ago.

“Hahahaha! Excellent! Excellent!” The doctor burst into exaggerated laughter.

“Then humanity will be saved by you. Because in the axis of time, causality… cannot be wrong.”

Carry your will forward. Go to the world where Earth can be saved. Seek the one and only solution to rescue mankind!

O Chosen One of Humanity.