The way to save Oh Jinwoo was simple.

Oh Yeon landed a precise punch on Lee Hansol’s abdomen and then hurled the groaning young man, writhing in pain, into his younger brother’s arms. The other researchers held their breath at such a bold move, but Oh Yeon showed no hesitation in his actions.
The one he couldn’t touch was the teacher, not Lee Hansol.

“Hyung, wait—!”
“If you want to live, stay put.”

The stern voice, laced with steel, made Oh Jinwoo clamp his mouth shut. It was their first conversation as brothers in ten years. Jinwoo had never been able to defy his older brother.

Lee Hansol, unable to either embrace or push away the confused Esper, whose hands hovered awkwardly in mid-air, grinned despite the pain twisting his features.
“Ha, haha, whew… Jinwoo, you really have a brother who’s your complete opposite, huh?”

“If you don’t want a hole punched through your head, keep your mouth shut.”

The owner of the menacing warning was Park Seungwon, leaning casually against the wall a few steps behind Oh Yeon. His forehead, damp with sweat, betrayed the urgency of his arrival, as did his uniform, still perfectly intact. Judging by the dazed tone of the staff member who had reported the situation, he must have rushed over in a hurry.

“Unlike our Yeon, I don’t care if Oh Jinwoo lives or dies.”

Lee Hansol shrugged as if to say he understood.

‘Father’ was completely absorbed in his experiment. At times like these, Father hated being disturbed. Hansol knew this all too well—his father’s word was an unyielding code to him.

Oh Yeon stepped out of the lab where his brother was and sat down on a bench, letting out a small sigh.

The pounding headache came sharply.

Perhaps because he was a cognitive-type Esper, Oh Yeon suffered from severe migraines whenever he was under extreme stress. His guide, well aware of this, lightly swept and kneaded the nape of his neck. Leaning into the touch, Oh Yeon closed his eyes and took a deep breath. Guides didn’t need to voice their emotions; they were naturally conveyed.

After a brief moment of relaxation, the Esper abruptly stood up from his seat. Park Seungwon offered him a faint, sympathetic smile as he observed his Esper’s resolute expression.

“…Go on.”
“Alright.”

Oh Yeon’s footsteps led him to the central research lab of the center.

There, all the cognitive-type Espers, led by Director Kwon Dahee, were gathered. The tension in the room was palpable, making the back of his head tighten uncomfortably. A middle-aged Esper stepped forward, displaying data on a large monitor as he began to speak.

“We’ve mapped all of the teacher’s movements within the center over the past three years using CCTV footage.”

What appeared to be a chaotic web of nervous red lines to the untrained eye was something entirely different to the cognitive-type Espers. They could analyze the dates and times marked at intervals as small as 0.01 millimeters.

Next, another Esper took their turn.

“This is a complete list of every guide the teacher has used so far. A total of 671 individuals.”

“Damn it. That’s disgustingly high… That psycho bastard…”

A muttered curse escaped from a corner of the lab.

Director Kwon Dahee, having reviewed all the data, spoke firmly and decisively. Her tone carried strength and authority. Gone was her usual elegant appearance; her hair was tied back in a simple ponytail, and she wore a loose T-shirt and jeans, reminiscent of her early days as a rookie researcher two decades ago.

“We have one month.”

“…”

“We must uncover, within these 30 days, how the Teacher commands suggestions from guides and find a way for him to survive without them.”

There was no time to wallow in helplessness. They had only one month—a period hard-won by Ji Gwanyeong and Choi Taehun. Oh Yeon stared at the monitor with such intensity that blood vessels seemed ready to burst in his eyes.

Choi Taehun did not blame either himself or his younger brother. He merely stared for a long time at Ji Gwanyeong’s retreating back as he walked out the door, before letting out a soft sigh.
That was all.

If only Choi Taehun had cursed him, blamed him, or even criticized him. That would have been easier to bear, less painful than this oppressive silence.

The Teacher’s proposal to seize control of all the Center’s power was startlingly simple.
One month.
He demanded one month from Ji Gwanyeong and Choi Taehun.

—

The Director’s office was heavy with silence, an eerie contrast to the considerable number of people seated inside.

On one side of the sofa sat Lee Miyeon, Oh Yeon, and Oh Jinwoo in order. Across from them, the Teacher lounged casually, legs loosely crossed, with Lee Hansol beside him.

Seated directly across from the Director were Ji Gwanyeong and Choi Taehun, the most perfectly matched pair in the Center’s history. Ji Gwanyeong’s grip on Choi Taehun’s hand was tight, as if he might lose him otherwise, and his face appeared just a touch paler than usual.

“Our Dahee’s taste has improved since becoming Director. Isn’t this a premium coffee bean?”

“…State your demands,” the Director responded curtly.

“So rigid.”

The Director studied every movement of the Teacher, from the way he placed his teacup down to his expressions. While his face and voice had changed, his gestures unmistakably matched the “Teacher” she remembered from the past.

Whose face was this? Whose voice had he stolen this time? Kwon Dahee bit her lip, trying to suppress her unease. But through the glint of her glasses, his snake-like gaze caught and read everything, accompanied by a sly smile.

“Well, I want to conduct a simple experiment. Truly, it’s a small price to pay for saving all those guides. Not just the guides—if they die, the Espers die too…”

“What kind of experiment?”

“Rising to a high position has made you interrupt people now?”

“Teacher!”

At Kwon Dahee’s sharp exclamation, the middle-aged man slightly furrowed his brow and shook his head, but soon replaced it with a mild, seemingly benign smile.

Choi Taehun flinched at the sight of that smile.

“Taehun-ssi.”

“…”

“I really like you, Taehun-ssi. I’ve said it before—Choi Taehun, you are the most ideal guide I’ve ever imagined.”

At the Teacher’s words, Lee Hansol’s brow twitched slightly. Oh Yeon, pretending not to notice, quietly averted his gaze.

“That’s why I want Choi Taehun-ssi to actively assist me in my experiment.”

“I’ll do it.”

The Teacher’s words were interrupted again, and his head tilted slightly, his smile never wavering. This time, the one who cut him off was Ji Gwanyeong.

Choi Taehun stared blankly at his pair with wide eyes. Ji Gwanyeong, the proud and dignified figure who detested being treated like a mere test subject, was now willingly offering himself up for the role.

“Whatever it is, I’ll do it.”

“Gwanyeong-ssi, what are you saying right now?”

“…Choi Taehun. Go wait outside.”

“How could you do this!”
Taehun’s voice grew desperate and loud.

But the Esper, unwavering, didn’t even blink, keeping his piercing gaze fixed on the Teacher. Ji Gwanyeong had seen Kim Gwonseok and his partner, Yoo Jinyoung, closer than anyone else. He had witnessed the tragedy—a guide who took their own life by hanging from the towering machinery of the training center ceiling, right before the eyes of their Esper, who could do nothing but watch.

If he could avoid becoming the protagonist of such a miserable story, Ji Gwanyeong was willing to do anything. He even thought that if what the Teacher truly wanted was an “experiment,” he was a better candidate than his partner, who had no regenerative abilities or immunity. It was a resolution the Ji Gwanyeong from a few months ago would never have made.

The Teacher seemed to enjoy the interruption. He smiled broadly, his eyes narrowing to crescents, and clapped with exaggerated enthusiasm: clap, clap, clap. Each clap felt like a dagger piercing Taehun, whose complexion paled visibly.

“This is exactly what I want, Taehun-ssi.”

The monster found it unbearable to hear his partner’s name coming from the Teacher’s mouth. But now, he couldn’t afford to let that displeasure show. The Teacher glanced at Ji Gwanyeong, who looked ready to tear out his throat, and grinned as if even that menacing gaze was amusing.

“Though Jinwoo here is also a strong Esper, Ji Gwanyeong is objectively the better choice in many ways. That Esper doesn’t let himself get swayed by sentimental nonsense. If necessary, he can be as ruthless as anyone—a remarkable advantage.”

“…”

“But what’s even more fascinating is how devoted Ji Gwanyeong is to his pair, Choi Taehun-ssi. Don’t worry, Taehun-ssi. The experiment will only require Ji Gwanyeong to put in a little effort.”

The guide didn’t respond to the Teacher’s words, pressing his lips tightly together.

The Teacher knew that expression well—it was Choi Taehun suppressing and concealing his emotions. Meanwhile, Director Kwon Dahee frowned and broke the silence.

“Teacher, get to the point. What exactly is this experiment you’re proposing?”

“I want to see the extent of a guide’s power.”

“…Power?”

“Yes, power. The kind of power that even the strongest Espers can never possess.”

The Teacher squinted, his tone dripping with amusement.

“Even Lee Hansol here, for example, only managed to take over the matching of an existing guide. He isn’t a real guide.”

Lee Hansol’s expression visibly stiffened.

Oh Yeon, for his part, committed every word and every subtle movement to memory. He could even count how many times Lee Hansol’s eyelids twitched during the Teacher’s speech.

“Now then, Taehun-ssi, let’s consider your greatest fear. That’s the theme of this experiment.”

Choi Taehun’s greatest fear.

The Director furrowed her brow, unable to predict what was coming next. The other Espers also appeared unsettled. But Ji Gwanyeong seemed to grasp the meaning of the Teacher’s words the moment they were spoken.

“First premise: ‘Esper Ji Gwanyeong and guide Choi Taehun are no longer matched.’”

Taehun’s expression, which he had been trying to keep composed, instantly faltered. The Teacher had struck a nerve, one buried deep within him.

Behind his glasses, the Teacher’s crescent-moon eyes gleamed dangerously.

“And I’ll add a few more experimental conditions to that. To make it more interesting, of course.”

“…Experimental conditions?”