Subtitle: When the student becomes the jailer, the teacher becomes a prisoner of his own ideals.
Dusk settled over the capital, feather by feather, like the dark wings of a crow descending.
Within Returning Clouds Manor, candlelight flickered in the depths of Shen Yuzhu's still eyes. He sat as motionless as a statue, his fingertips unconsciously resting upon the barely dry ink stains—the frantic words "Protect Her" he had scrawled during his collapse, then attempted to erase after the mirror toxin's feverish blaze the night before.
The door opened without a sound.
A black-feathered lantern entered first, its light casting long shadows. The deep blue robes of its bearer flowed like night mist in the dimness. Xuan Ya stood at the threshold, her voice as soft and measured as in remembered days:
"Teacher, I've come to see you."
Shen Yuzhu did not look up, his tone flat, as if carved by a ruler: "The Night Crow Division's tea remains as bitter as ever."
"Bitterness is the taste of reason," Xuan Ya stepped forward slowly, placing the lantern on the corner of the desk, "as you taught me."
She leaned forward to pour the tea, her movements elegant and precise, a ritual in itself. A subtle, cold fragrance drifted from her sleeves. The tea appeared clear, yet it refracted a strange, indigo gleam in the candlelight.
"The chill toxin within you," she pushed the cup closer, the candle's flame dancing in the depths of her eyes, "I've always believed it to be the most beautiful form of reason. Today, I shall let reason take its first breath."
She watched the teacup, her fingertips trembling almost imperceptibly.
"The Door of Reason opens only for the clear-minded... Teacher, you taught me that."
Outside the courtyard wall, the wind grew sharp, carrying a biting chill.
Gu Changfeng's knuckles whitened on the hilt of his sword. "The Night Crow Division's 'Silent Knot' has sealed this place tight as an iron barrel."
In the shadows of the corridor, the silver bell in Lu Wanning's hand trembled silently. "The barrier is complete. Forcing it from the outside would shatter the hearts and meridians of everyone within."
"Then we break it from within." Gu Changfeng's gaze was sharp as a honed blade, having already pinpointed the weakest node of the barrier's energy.
"Breaking from within requires someone to enter first—it's a suicide mission."
He turned his head slightly, his voice low as he looked at her calm profile:
"If you go in, I go."
Her fingers trembled once over the compass—then stilled. She didn't argue.
The moment the tea touched his lips, Shen Yuzhu heard the sound of the world shattering—
like distant chains being pulled taut, like a massive, ancient door slowly turning on its axis deep within the fortress of his own reason.
Icy rationality exploded through his veins. His body temperature plummeted; his very breath seemed to transform into numerical values. The candle flame decomposed into streams of data; the shadows on the wall became flowing code. He was violently thrust into a world woven entirely from equations—every thread of existence calculated, judged, and then coldly erased.
Snow and fire overlapped at the edge of the algorithm. Chu Hongying stood in the blizzard, a poisoned arrow—the very one he had handed her—piercing her chest. She smiled, a smile that his parsing reason labeled as an "unnecessary emotion." A colorless, frigid voice echoed in his mind: "Sacrifice her, and it all ends. This is the optimal solution."
His brush frantically scratched across paper—Protect Her, Protect Her, Protect Her.
Each repetition carved another fracture into the pristine code that bound him.
The ink was still wet, yet he was the one feeding the pages into the fire. Ashes rose, coalescing and burning into a cluster of frostfire in his palm: ice crystals and flame intertwined, its light unbearably bright, bright as a frantic heartbeat.
The blizzard returned, mirrors cracking. Helian Sha stepped from the fissures, his form overlapping with a wolf's shadow.
"Reason?" He laughed softly, a sound devoid of warmth. "No—it's only your excuse for being afraid to truly live."
"Beasts understand pain; humans justify it. Your reason is nothing but fear—frozen solid."
He drove his bone blade into the ice, and cracks spread radially across the entire snowfield.
"If you truly wish to save her, stop being the man trapped in the mirror."
Shen Yuzhu raised his hand. The frostfire still burned in his palm.
Ice and fire merged; the extreme cold transformed into pure, incandescent light.
In that very moment—
He heard an exhalation from a distant, immeasurable depth.
Not the wind, not a heartbeat, but the slow, heavy breath of some ancient, slumbering existence.
The entire space trembled in resonance; the bronze mirror on the desk rippled like the surface of water.
Xuan Ya snapped her head up, shock flashing in her eyes for the first time. She could perceive it—an energy, vast and beyond her comprehension, was stirring awake.
Shen Yuzhu suddenly understood:
The boundary between reason and emotion—that is where the Door resides.
When ice and fire merge, when mirror and heart resonate as one, the Door will crack open.
For the first time, he heard—
The sound of his own heartbeat gradually synchronizing with that ancient, rhythmic breath.
In the west wing, Chu Hongying jolted awake from her forced rest.
The blood oath mark on her chest burned like a red-hot brand, a pain both icy and searing tearing through the connection they shared. Through it, she "saw" him—sitting alone in the crumbling ruins of his reason, an endless abyss yawning wide behind him.
"Shen Yuzhu!" Using her formidable will as a blade, she cleaved through the hallucinogenic haze binding him, "If you dare die trapped in your own reason—I will never forgive you! Do you hear me!"
The impact vanished like a stone sinking into a still sea, the backlash drawing a thin line of blood from the corner of her lips.
"It's useless." Lu Wanning steadied her trembling hand, the physician's gaze locked on the madly spinning jade beads of her delicate compass. "The frost toxin and the hallucinogen are merging within him—this is the violent rejection before a fundamental transformation. Forcing an intervention now will only shatter his mind."
The candle wick snapped with a sharp crack.
Xuan Ya calmly observed the frostfire phenomenon manifesting around him and the faint, almost imperceptible tremors in the space itself. Quickly recording every detail of the data, she rose, leaving behind a single, stark black crow feather. A plain note lay beneath it, the ink still fresh:
"Teacher, the Night Crow Division awaits your return."
The door closed softly. Shen Yuzhu faced the dying candle alone, his murmur barely audible, as if spoken in a dream:
"I built a cage of reason... yet I could not cage a single moth that burns itself for me."
In the corridor, the embers of tension had not yet cooled.
Lu Wanning lowered her gaze, a silver needle twirling once between her fingers before its light vanished.
"Don't act rashly," her tone was deceptively steady, "We hold our position—we wait for the one inside to break through himself."
Gu Changfeng fell silent for a long moment, finally sheathing his sword with a soft, definitive click.
The wind poured into the courtyard, making the ironclad barrier hum silently.
He raised his eyes towards that solitary, flickering candle flame, his voice low but resolute:
"If he cannot come out on his own... we will go in and bring him back."
In the imperial study, a bronze mirror gleamed with a faint, internal light.
The Emperor trailed his fingertips over the mirror's cool surface, which reflected the frostfire pulsing in Shen Yuzhu's palm and captured even the faintest ripple in the space around him.
For a brief instant, their heartbeats echoed through the same mirror.
An attendant knelt, reporting in a hushed voice: "Your Majesty, the Night Crow Division's signal has been delivered."
"Good." The Emperor's finger paused over the reflected image, "Let the Door of Reason open once more."
He lifted his gaze to the heavy, starless night enveloping the capital:
"When the old reason collapses, the world itself... can be remade."
He watched that cluster of frostfire in the mirror, as if seeing the first dawn of a new, reborn order.
And that distant, ancient breath echoed faintly through the mirror, resonating with the steady beat of his own heart.
[Ending - Version 3: Resonance Eruption]
The frostfire in his palm pulsed, throbbing like a second, living heart.
Then—an unfamiliar, yet fiercely familiar presence surged from the deepest part of his being.
Not the Emperor's watchful gaze, not the cold breath of pure reason.
It was her.
Chu Hongying's voice, clear and unwavering, came from the other side of the crumbling Door,
"I am here."
Light and flame erupted in a silent cataclysm—
the meticulously constructed worlds of reason, the turbulent seas of emotion, and the primal forces of instinct collapsed into one another all at once.