Chapter 25: The Elevator Stopped at a Nonexistent Floor

The surveillance footage played in a silent loop on the screen.

Cold pixels faithfully recorded everything that had transpired after 2:00 AM. In the study, "Shen Mo" himself—the man who should have been fast asleep in the bedroom—had walked to the desk like a sleepwalker. He gripped a fountain pen and mechanically wrote the same sentence on a sheet of white paper, over and over again.

"We didn't finish the walk."

Three times, no more, no less.

The handwriting possessed a rigid, inhuman precision. Shen Mo did not even need to perform a sophisticated image comparison; one glance was enough to send a chill rising from the pit of his stomach. This handwriting was identical to the residual text formed of blood and dust on the thirteenth step.

This was not an imitation; it was a manifestation. Something was using his body to continue its unfinished "walk."

He forced himself to stay calm, his fingertips flying across the keyboard to pull up the data logs from the back end of the instructional video. The data flow following the video's upload had been calm and undisturbed, right up until last night.

Starting at 1:50 AM, a series of anomalous requests had flooded in. There were thirty-seven instances, each IP address masked by layers of obfuscation, yet the final source pointed, without exception, to the internal surveillance systems of old, abandoned buildings scattered across the city. They were like an invisible spiderweb, quietly connected, collectively peering at him.

What made his scalp crawl even more was the playback log. At 2:13 AM, while he was unconsciously writing those three lines, a visitor had watched the entirety of his uploaded "M8313 Project Simulation Acceptance" clip. The video progress bar had paused at the very end for exactly thirteen minutes.

The thirteenth minute... Shen Mo’s gaze snapped toward the desk.

At that exact moment in the surveillance footage, the fountain pen that "he" had set down rolled off its rest without warning, carving a slanted, heavy line across the paper filled with text. The shape looked like a scrawled letter, or perhaps a room number.

B4.

Just then, the doorbell rang. Su Wangying had brought the latest emergency report from the museum; her face was as pale as the document in her hand.

"Things are not looking good," she said, getting straight to the point, her voice low. "The 'emotional condensate' inside the safety helmet... it has spread."

She spread several high-resolution photos across the table. What had originally been a faint residue on the lining fibers was now, like a living thing, spreading along the inner walls of the sealed display case, forming an intricate network of micro-cracks.

"We compared the crack network topology with the original blueprints for the M8313 staircase," Su Wangying said, pointing to another document—a color-coded stress distribution map for the timber. "Look, the structure is shockingly similar. It isn't spreading randomly; it is replicating... not just the memories of the deceased, but the 'rules' of that space."

Shen Mo's heart sank. A bold and terrifying hypothesis formed in his mind. If a residual echo could replicate rules, could it, like a virus, infect other similar "hosts"?

"Wangying, check the recent public notices from the Municipal Construction Commission."

***

A few minutes later, the answer appeared on the computer screen. Within the past week, three reports of similar nature had all pointed to the same location: the old Xinhua Department Store building, scheduled for total demolition. The reports sounded like urban legends: when riding the freight elevator, the elevator would stop at an extra floor.

"Xinhua Department Store..." Su Wangying muttered, quickly pulling up the files. "The design firm is the same. The blueprints for the M8313 batch of staircases and those of the Xinhua Department Store were drawn by the same lead architect."

The mystery was solved. The residual echo was using its own logic to find and "infect" buildings of the same origin. It was expanding.

Shen Mo immediately applied for access to the Xinhua Department Store under the guise of a "pre-demolition structural safety review." The project manager, Engineer Zheng, a middle-aged man with a perpetually impatient expression, showed strong resistance over the phone.

"Review what? The elevator system has been out of service for a long time; the power is cut for safety reasons. Don't come here to make trouble with your research," Zheng's voice was coarse and firm. "And another thing, don't believe those boring reports. This building only has two basement levels for storage. There is no B3, let alone a B4!"

Zheng's denial only made Shen Mo more certain. He did not argue further. After hanging up, he drove directly to the site. Using the excuse of inspecting fire exits, he easily bypassed the security and found the maintenance entrance leading to the elevator shaft.

A cold iron ladder extended into endless darkness. Shen Mo turned on his headlamp and slowly descended along the shaft wall. The air was thick with the musty smell of mixed engine oil and dust.

About fifteen meters down, his beam caught something unusual. On the smooth concrete wall of the shaft, there was a perfectly regular outline of a door frame that had been re-sealed with cement. Along the edges of the frame, fragments of mottled red paint flickered in the light—the uniform paint used for the counters of the state-run "Night Market Golden Street" in the 1980s.

There had once been a door here.

Shen Mo took out a canister of fluorescent spray and coated the wall around the door frame evenly. Then, he turned off his headlamp and switched on a handheld UV light. Under the eerie purple glow, a shocking sight emerged. From the third-floor level where he stood and downward, rows of previously invisible floor labels appeared, emerging from deep within the cement in reverse order, glowing like ghost fire.

B3, B2, B1, G, 1...

These labels were not being uncovered; they were being "filled in" by a reverse flow of time. The space was growing from a non-existent "future" back toward the known "past."

To verify the "trigger by skepticism" mechanism that had been circling in his mind, Shen Mo returned to the ground floor and, together with the waiting Su Wangying, managed to connect the backup power to the freight elevator.

Inside the elevator car, the atmosphere was heavy. Shen Mo looked at Su Wangying and deliberately said in a dismissive tone, "This building doesn't have a B3, and this so-called B4 is complete nonsense."

No sooner had the words left his mouth than the elevator shook violently, followed by a teeth-grinding screech of metal, and it plummeted!

***

The emergency braking system did not respond. However, the high-precision accelerometer in Shen Mo’s pocket displayed a bizarre data curve—it was not a free fall.

After falling for about 6.8 meters, the entire elevator came to a hovering pause for 0.7 seconds, as if supported by an invisible hand. In that moment of suspension, the previously dark floor display screen flickered to life with a "buzz," and two scarlet characters emerged: B4.

The elevator doors slid open smoothly. Outside was not a basement, but an airtight room. The room was filled with all kinds of vintage radios, and hundreds of speakers were simultaneously playing the same news recording. A raspy male voice echoed in the cramped space:

"...The city's rectification work regarding the individual economy is proceeding steadily. For illegal vendors occupying the streets and affecting the city's appearance, we will resolutely crack down..."

Su Wangying’s breath hitched. "I checked the archives. This is the local news broadcast from the evening of April 17, 1983. That was the day the underground night market at Xinhua Department Store was permanently sealed."

They did not linger, quickly retreating from that eerie space. Back in the car, Shen Mo immediately pulled up the call recording of the last missing maintenance worker—the final call made to the dispatch center before he vanished.

Shen Mo imported the audio into his computer, filtered out the electrical noise, and amplified the background sound to the limit. Amidst the worker's panicked shouts, a faint, fleeting sound was captured.

It was the crying of a newborn, lasting less than 0.3 seconds.

Shen Mo felt a jolt. He suddenly recalled a long-forgotten folk rumor Su Wangying had mentioned about the Xinhua Department Store: when the underground night market was closed, a pregnant vendor who was about to give birth went into premature labor during the chaos, and both mother and child perished.

The clues were linked. He immediately compared the original construction blueprints of the Xinhua Department Store with the scanned copies downloaded from the urban construction database. The drawings had been modified multiple times, covered in red and blue pencil marks. Finally, in the corner of a ventilation duct design for the B3 level that had been scribbled over beyond recognition, he found a line of pencil text that had almost been worn away.

"B3 Night Market, Stall 87, Pregnant Woman Chen XX, First Aid Record Archive Number: M19830417."

He had found the source. The core of the residual echo was not the cold architecture, but the despair of a mother and her unborn child.

Shen Mo immediately picked up his phone and dialed the night duty line of the municipal archives, wanting to verify the number. On the other end of the line, there was only a long, dead silence.

Just as he was about to hang up, his phone screen suddenly lit up, and a new text message popped up. The sender was a string of garbled characters.

The content was only one sentence.

"The record you want to check... tonight at three, see you at the archives."