302: sewer

Inside the door was a darkness so thick it almost felt solid. The flashlight's beam cut only a limited path, revealing thick layers of dust on the ground and the blurry outlines of miscellaneous debris nearby.

A stale, slightly sweet and bloody scent permeated the air.

Shen Mingyuan stepped inside, his flashlight sweeping across the unknown darkness ahead. Taking a deep breath, he spoke slowly in the most theatrically dramatic, low voice he could muster:

“Behold, my friend. This forgotten corner, this temple abandoned by time... it silently recounts hidden secrets.

Every grain of dust is a silent witness; every thread of darkness weaves...” He even paused deliberately to build suspense, “...a spiderweb leading to the truth.”

“Stop, stop, stop! Cut it out! Shen Mingyuan, stop reciting that!” Beside him, Lu Jianchuan abruptly raised a hand to cover half his face, his voice filled with undisguised embarrassment and amusement.

“I’ve got goosebumps, and my toes are practically digging a three-bedroom apartment into this floor! We're here to investigate a case, not to voice-act for some Detective radio drama! Please, just be normal!”

Shen Mingyuan paused, seemingly wanting to say more, but he eventually sighed and finished in a tone that suggested 'you Mortals simply don't know how to appreciate art':

“...Fine. Since you cannot appreciate the poetry and atmosphere this journey of exploration deserves, I shall temporarily... forgive your lack of romantic sensibility and cease this narration of destiny.”

“Here he goes again...” Lu Jianchuan pressed a hand to his forehead, deciding to ignore his partner's occasional bouts of 'professional chuunibyou' and focus back on the environment itself.

The two carefully explored the small space. It truly looked long-abandoned; the furniture was covered in thick dust, and the air was stagnant. However, Shen Mingyuan soon noticed something was wrong. He crouched down, pinched a bit of dust from the floor between his fingers, and examined it closely under the light.

“Brother Lu, the dust is thick enough... but it's a bit too uniform. And,” he blew gently on it, frowning at the way the dust scattered, “the way this dust settled doesn't look like natural accumulation over several years. It looks more like... someone recently moved around here and then deliberately spread a new layer over a large area to cover up footprints and traces.”

“Spread a layer?” Lu Jianchuan grew alert, his gaze sharpening as he scanned the floor and the surfaces of the furniture.

Their search immediately gained focus. Soon, Shen Mingyuan stopped in front of an old wooden bookshelf against the wall. The dust on this shelf was ridiculously thick, almost obscuring its original color, making it stand out oddly compared to its surroundings.

“It's here.” Shen Mingyuan stepped back and signaled to Lu Jianchuan.

Understanding the cue, Lu Jianchuan wasted no words. He stepped forward and delivered a powerful kick to the side of the bookshelf.

“Boom!”

The already flimsy old bookshelf collapsed sideways as expected, kicking up a choking cloud of dust. Behind it, a seemingly ordinary wall was revealed. Shen Mingyuan stepped forward and tapped on various parts of the wall with his knuckles.

“Thump, thump, thump...”

Unlike the dull sound of a solid wall, a distinct hollow echo came from the area behind the bookshelf.

The two exchanged a look and nodded.

Lu Jianchuan transformed immediately. A silver-white biological armor instantly covered his body.

Then, he slammed a fist hard against the hollow-sounding section of the wall!

“Bang—Crash!”

The disguised layer shattered, revealing a dark, narrow passage entrance extending downward. A thicker, indescribable draft of air surged out from the depths.

Facing the pitch-black passage, Shen Mingyuan didn't hesitate either. Following right after Lu Jianchuan, he completed his transformation. The matte black armor of his Shadow Form silently covered his body, and his red eyepieces glowed faintly in the dark.

One after the other, using the enhanced physical capabilities of their armor, they felt their way down the narrow, steep passage. The passage twisted and turned, seemingly utilizing some architectural gap or abandoned piping, extending continuously downward.

After descending an unknown depth, a rusted iron grate door finally appeared ahead. Lu Jianchuan ripped it open with a bit of force. A pungent stench, so thick it felt almost tangible—a mix of rotting matter and chemical agents—surged out. Even through the biological filtration systems, it was enough to make one feel nauseous.

Before them was a wide but filthy underground corridor. The walls were rough concrete, and a shallow stream of murky water flowed beneath their feet. The distant sound of rushing water could be heard—a typical main structure of a city sewer.

“Tsk.” Shen Mingyuan couldn't help but groan. Even with the armor's filtration, that complex, intense stench was still highly penetrating, assaulting his highly sensitive sensory System and causing strong physical discomfort.

“Can't be helped, just bear with it.” Lu Jianchuan's voice came through the armor as he looked around. “What about those ‘Detective tools’ of yours? Ultrasound or thermal imaging—can you scan for anything useful? There are probably a lot of forks in this place.”

Shen Mingyuan nodded, temporarily disabling his enhanced sense of smell to concentrate. He first closed his eyepieces and switched to thermal vision. In an instant, the world became a series of blurry outlines defined by different temperatures.

The walls were a cold deep blue, the water at their feet was a slightly warmer dark green, and behind some pipe gaps and piles of debris, he saw many small, fast-moving orange-red dots—rats, insects, and other small creatures adapted to the dark. He found no obvious human or large biological heat sources.

But that wasn't enough. He reopened his eyepieces, took a deep breath, and activated active sonar. He crouched slightly, and a biological membrane in his chest cavity emitted high-frequency vibrations inaudible to normal people.

The sound waves fanned out from him, striking the walls, pipes, water surface, and various obstacles before quickly bouncing back.

The feedback information rapidly constructed a detailed, real-time 3D structural map within his red eyepieces. He 'saw' a fork in the path thirty meters ahead, the crisscrossing layout of pipes overhead, and... “Wait.” Shen Mingyuan suddenly crouched down, pointing to a patch of seemingly solid concrete floor by his feet. The sonar image clearly showed that about two meters below it, there was another parallel, more regular spatial structure.

“There's another level... below this. And there's a non-naturally formed passage connecting them.”

“Can you find the entrance down?” Lu Jianchuan asked, his gaze scanning the murky surroundings.

Shen Mingyuan didn't answer immediately. He slightly adjusted his stance and direction, like a precision radar slowly scanning. In the vision behind his red eyepieces, the underground structural map constructed by the sound waves constantly fine-tuned and refreshed as he moved.

“The structural layers are too thick; the echo signal is attenuating heavily.” He explained as he moved his feet, his voice sounding somewhat muffled inside the helmet. “ I can only barely perceive the ‘outline’ of a non-natural space below, but as for the specific entrance... I need to find the position with the strongest signal, which would be the thinnest part of the structure or a point with a connecting passage.”

As if listening to echoes that an ordinary person couldn't catch, he slowly moved forward a few meters, stopped, and shook his head: “Not here... the solid mass is too thick.” He stepped back a few paces, turned to the other side, and slowly investigated along the edge of the water flow.

“This way... too much interference; the noise from the water and pipes is confusing things.” He adjusted his direction again, walking toward a relatively dry area where the wall looked more intact.

“Wait... the echo here is a bit different.”

Shen Mingyuan stopped in front of a seemingly unremarkable concrete wall. He leaned his side against the wall, even pressing his palm gently against the rough surface, as if he could feel minute vibrational differences through his armor.

“The sense of hollowness... is clearer. The shape of the ‘blank zone’ behind it seems more regular.”

He moved laterally along the wall, the light of his red eyepieces flickering slightly as he concentrated fully on analyzing every minute change in the acoustic feedback.

“Keep going... this way, the signal is strengthening... it should be right around here.”

His tone took on a certain edge, and he finally stopped at a corner where the base of the wall met the floor. A pile of semi-rotted debris and sludge lay here, looking filthier and more cluttered than the surroundings.