Chapter Twelve – All Who Heard It Were Dead

This thought struck like a cold bolt of lightning, cleaving through all the tangled threads in Shen Mo’s mind.

He immediately retrieved the complete duty records from the city’s psychological support hotline, focusing on the last twelve hours of Zhou Zhenguo’s shift before his death.

The electronic files coldly displayed the facts: around the time of the distress call marked “unknown origin, untraceable,” Zhou Zhenguo’s call logs showed three complaints.

The complaints were strikingly similar, all pointing to his poor work condition—“a cold tone, as if reading from a script,” “completely lacking empathy, just going through the motions,” “I felt like I was talking to a robot.”

Behind each complaint was a handwritten note from Supervisor Li: “Interview conducted.”

But beyond those three words, there were no further follow-up actions.

Shen Mo summoned Supervisor Li for a meeting.

This middle-aged woman, who had worked at the hotline center for nearly twenty years, bore a face etched with professional fatigue and a trace of undeniable panic.

At first, she responded with official platitudes, emphasizing that Zhou Zhenguo was a veteran employee, skilled in his duties, and occasional emotional fluctuations were inevitable.

But when Shen Mo placed copies of the complaint records before her, her defenses completely shattered.

Her voice choked, and she confessed everything.

“Old Zhou… had it rough.” She lowered her head, fingers nervously twisting the edge of her clothing. “His wife became a high-level paraplegic seven years ago due to a medical accident. He took care of her all by himself. Over the years, he was like a taut string—working by day, then at home doing rehabilitation, feeding, turning her over at night, barely ever sleeping through a whole night.”

The prolonged mental stress had caused Zhou Zhenguo to develop severe depression. At work, he often seemed absent-minded, as if his soul had detached from his body.

Supervisor Li had noticed long ago and even considered transferring him to a logistics role, but the center was perpetually understaffed, and new recruits couldn’t fill the gap. So the matter dragged on and on.

“I thought it was just ordinary emotional stress; a little counseling and a few days off would help him recover.” Tears finally slipped down Li’s cheeks, her voice laden with regret. “I never imagined… I later learned that every day after work, he would lock himself in his study and repeatedly listen to that failed rescue call recording. He wasn’t analyzing or investigating; he was punishing himself. That humming wasn’t noise to him—it was judgment. He sank deeper and deeper until he became part of the echo itself.”

Shen Mo listened quietly, the logic chain about the “residual echo” in his mind now firmly welded by Li’s tearful account.

He recalled Zhao Wan’s breakdown in the interrogation room, repeatedly saying, “I should have stopped her.” The guilt of failing to prevent her friend Lin Wanqing’s death mirrored Zhou Zhenguo’s remorse over the failed rescue.

A bold and clear hypothesis took shape in his mind: the “residual echo” was not random interference; it was like a predator with a keen sense of smell, precisely targeting those burdened with intense guilt and “unfinished responsibilities.”

These people, due to their own mistakes or helplessness, bore an unfillable void in their hearts, and the humming of the “residual echo” was the poison filling that void.

He immediately applied to Sun Tao to retrieve all the files on unusual deaths in the city over the past six months.

Amid the mountain of archives, he quickly found more evidence.

A firefighter, after a misjudgment during a blaze that failed to rescue the last trapped child, hanged himself a fortnight later with a fire hose at home, repeatedly mentioning strange singing to colleagues before his death; a surgeon, due to a diagnostic error that caused a patient to miss the optimal treatment window and die, suddenly suffered cardiac arrest while on duty in the operating room, with footage showing him murmuring to an empty intercom before dying; a high school homeroom teacher, who ignored the distress signals of a depressed student leading to the student’s suicide, was found dead a week later in his car, with the car radio playing an unidentifiable static noise repeatedly…

All the deceased shared one common trait: they had all interacted with some form of public communication device before death, and autopsy reports without exception showed very slight diffuse bleeding points in their brains, consistent with symptoms caused by prolonged exposure to specific frequency infrasound.

The “residual echo’s” hunting ground was spread throughout the city.

Shen Mo and Su Wanying returned once more to that abandoned commercial-residential building.

This time, they were no longer aimless.

Using the precise coordinates of Zhao Wan’s last phone signal, they went straight to the basement level two.

The cold, damp air was heavy with the smell of rust and mold. At the corridor’s end stood a heavy iron door, rusted shut.

There was no lock on the door; it appeared to have been welded from the inside.

Shen Mo pried at it with a crowbar, exerting every ounce of strength to force open a gap.

With a grating creak that made their teeth ache, the iron door was forced open.

What lay beyond stunned them.

There were no complex machines, no altar, and no corpse.

The room was empty, four walls bare, save for an old-fashioned black rotary phone hanging on the wall opposite the door.

The phone’s receiver hung lifelessly, its long coiled cord severed and resting on the dust-covered floor like a dried umbilical cord.

This was the source.

Shen Mo gestured for Su Wanying to step back and donned the highest-grade industrial noise-canceling headphones.

He took a long-handled insulated plier from his toolbox and carefully gripped the broken cable’s connector, linking it to the probe of a portable oscilloscope.

The moment the circuit connected, the oscilloscope’s screen shifted from a steady green line to wild peaks and troughs.

Inside the headphones, that familiar, scalp-tingling humming returned—but this time, the background was no longer hollow silence.

Countless fragmented, overlapping whispers filled with despair and resentment surged like a tide from the depths of hell, instantly overwhelming his hearing.

“...Why didn’t you listen... you could have saved me...”

“...You should have been there... you promised...”

“...Can you hear it... what you should hear...”

Su Wanying stared at the chaotic waveform on the oscilloscope, then at the lonely phone on the wall. She pulled an ancient stitched-bound book from her cloth bag and flipped through it rapidly before pointing to a page and whispering to Shen Mo, “‘Records of the Yiji Hall Funerary Affairs’ mention something called the ‘Proxy Voice Chamber.’ It says that in some places, because of too many unanswered cries for help and wishes, over time, these obsessions attract and merge with each other. They cease to be individual souls and become a ‘river of resentment.’ This place… is probably the estuary of that river.”

“If it’s a trap set by exploiting people’s sense of responsibility and guilt,” Shen Mo said, removing his headphones, his eyes sharp, “then we can turn this mechanism against itself.”

A bold plan quickly formed in his mind.

He returned to the bureau and recorded a simulated audio clip overnight.

He took the fundamental frequency of the “residual echo” humming as a base but completely altered its harmonic structure, layering over it a deep baritone voice delivering psychologically soothing and calming frequencies: “Your responsibility has ended. Your call for help has been heard. The departed have found peace. Please lay down your burden.”

Then, using his authority, he embedded this “antidote” audio into the backup encrypted channel of the police communication system and applied for it to be automatically played at the end of every call on all psychological crisis intervention hotlines across the city. The clip lasted just five seconds.

Three days later, Sun Tao brought him a data report, his expression conflicted.

“It’s effective,” he said. “Across the city, passive exposure to abnormal voiceprints dropped by 83% within seventy-two hours. But… we’ve discovered a new group of abnormal cases.”

The report showed that many initially flagged as “potentially contaminated” had indeed lost the abnormal brainwave fluctuations, but they developed new symptoms—aphasia.

These people no longer heard the humming or suffered nightmares, but they had lost the ability to speak.

The latest functional brain scans revealed that their language centers had been forcibly “paused” by an invisible hand, entering a deep, non-organic suppression state.

Shen Mo’s heart sank.

He understood: the “residual echo” had not weakened; it was merely retreating.

It had replaced “calls for help” with “silence,” evolving into a more covert and terrifying form of contamination.

It was telling all those it had marked: since you have heard it, now you must forever be silent.

Late at night, the task force office was empty except for Shen Mo.

He sorted through piles of data alone, trying to find a new breakthrough among the “silent-type” contaminated.

Suddenly, his phone vibrated violently without warning. On the screen, a glaring message flashed: Unknown Number.

He did not answer, letting the monotonous ringtone echo through the empty office.

Yet, after ringing for a full minute without being answered, the call did not hang up; instead, it connected automatically.

The receiver was filled with dead silence—no sounds, no humming, no static.

Only a faint, almost imperceptible rhythm.

It was a breathing pattern, subtly captured and amplified through the phone’s microphone.

Shen Mo’s pupils contracted sharply—this frequency, this pattern of throat muscle vibration, perfectly synchronized with the breathing he heard from the monitoring device when Zhao Wan was deeply contaminated.

He slowly and stiffly lifted his head, staring at the large floor-to-ceiling glass window in the office.

Outside were the myriad city lights, while inside, condensation had formed a thin layer of mist on the glass due to the temperature difference.

On that mist, as if traced by an invisible finger, a line of words slowly appeared, stroke by stroke.

The handwriting blurred at first, then sharpened, finally fully materializing before his eyes:

You have heard it… so you, too, must be silent.

Shen Mo stared fixedly at the line of words formed from moisture, his finger hovering over the red hang-up button on his phone but hesitating to press it.

His gaze passed beyond the words, looking out further into the street.

At that moment, he saw the old-fashioned public phone booths lining the main road beneath his feet, stretching to the city’s edge.

The once dim red call indicator lights seemed to receive the same command, lighting up one after another in the deep night, silently and simultaneously.