240: ancient city

Wei Ziqing looked at the plant staircase that emitted a soft glow and had inexplicably "grown" out of the abyss. He swallowed hard, his voice sounding a bit weak:

"Are... are we really going up? This... looks a bit... too mysterious, doesn't it? Is it reliable?"

Lu Jianchuan didn't answer immediately. He walked to the edge where the stairs connected to the cliff, crouched down, and carefully examined the jade-like, wood-like material that formed the main trunk of the staircase.

He pulled out a multi-functional tactical baton he carried with him, extended it, and then used the tip to poke the nearest "step" and the surrounding railing vines forcefully. They felt hard yet elastic, remaining completely still.

He then took off his backpack—which was filled with quite a bit of equipment and wasn't light—and gently placed it on that section of the plant staircase. The stairs didn't even bend slightly; they were as stable as if they had grown there since ancient times.

"The structure is very stable, with sufficient load-bearing capacity." Lu Jianchuan stood up and made his judgment, his tone decisive. "I'll lead the way. Follow behind me, keep your distance, and watch your step." With that, he hesitated no longer and stepped onto the glowing plant staircase.

Seeing this, although Professor Chen's heart was filled with shock and doubt regarding this supernatural phenomenon, his desire for exploration and obsession with solving the mystery of "Bai Ze" prevailed. He took a deep breath and nodded to his students. "Be careful, follow Mr. Lu."

Cynthia said nothing, only silently checking her equipment before following the professor onto the stairs.

Wei Ziqing and Shen Mingyuan glanced at each other. Shen Mingyuan's deep red goggles flickered with light, seemingly using ultrasound or other means to quickly scan the massive plant structure. After a moment, he gave Wei Ziqing a nearly imperceptible nod.

"Let's go down," Shen Mingyuan said.

Thus, the group, along with several GUPA armed personnel responsible for protection, stepped one by one onto this glowing path leading to the unknown abyss.

The plant staircase was wide and steady. Walking on it, they felt almost no swaying, only a slight elasticity beneath their feet.

Only as the cliff walls on both sides gradually receded, replaced by more darkness and the milky-white fluorescence emitted by the plants below, did they truly realize how vast an underground space they were descending into.

They walked down the spiral staircase for a long, long time.

There were only the sounds of footsteps, breathing, and the occasional slight rustling from the plants, as if they were growing. The entrance above had long since vanished from sight and the halo of light, and the destination below seemed equally unreachable.

They seemed suspended in a corridor of light, slowly descending through the boundless darkness.

After an unknown amount of time, the stairs beneath their feet finally stopped spiraling around the cliff wall. They reached the very bottom of the plant. By now, the surrounding rock walls had long since disappeared, and extending beneath them was an exceptionally flat and hard "ground." They stepped off the final plant stair and truly entered the bottom of this underground world.

This was a massive space, unimaginably vast.

Above them was a pitch-black void with no visible ceiling, as if there were no dome, only nothingness.

Beneath their feet was an astonishingly flat ground, its material neither stone nor soil, feeling hard and cold to the touch. It extended infinitely in all directions until it was swallowed by the thick darkness.

The giant plant that had provided the staircase was now the only light source in this boundless darkness. However, the milky-white fluorescence it emitted seemed weak and tiny in the face of such vast emptiness, only able to illuminate a limited area around them.

Beyond the halo of light was pure, heavy darkness that felt almost tangible. No outlines could be seen, no echoes heard; there was only a heart-pounding sense of vastness and silence, as if even time had stood still.

"This... this is just too big..." Wei Ziqing marveled in a low voice, his words sounding exceptionally small in the emptiness.

The male student, Xiao Wu, perhaps felt some gratitude for the strange plant guiding their way, or maybe it was just a young person's instinctive affinity for plants.

He put down his backpack, took out his water bottle, unscrewed the cap, and while muttering "Thank you, you've worked hard," he carefully poured a bit of the little water he had onto the plant's branches near the roots.

The fresh water seeped into the jade-like surface of the branch and seemed to be quickly absorbed.

Immediately after, the milky-white fluorescence flowing on the plant's branches brightened visibly. Within the light, a faint hint of vibrant, emerald green vitality even emerged, and the illuminated area around it expanded slightly.

Other than that, there were no other changes.

Standing in that tiny halo of light, facing the boundless darkness and emptiness in all directions, a feeling of near-disorientation seized everyone.

"Now... which way do we go?" Wei Ziqing's voice sounded a bit dry in the silence. As far as the eye could see, there was nothing else except the flat ground beneath them and the glowing plant—not even a landmark.

"We can only pick a direction for now," Shen Mingyuan said in a deep voice. His deep red goggles scanned the darkness, but even with his long-range vision, he couldn't see the boundaries in the lack of light and such a massive scale. "Maintain formation. Watch your step and your surroundings."

Using the glowing plant as their origin, the group chose a random direction and stepped cautiously into the darkness. They walked slowly, using their limited light sources and Shen Mingyuan's perception to find the way.

The ground beneath them remained that hard, flat surface. After walking for a while, they felt the ground begin to slope slightly downward, and steps appeared—neatly cut steps made of the same material as the surrounding ground, descending level by level.

They followed the steps down, their light sources shining in all directions. Where the light passed, it was no longer empty.

First came vague outlines, followed quickly by a clear sight—houses.

They were ancient wooden structures. Although they had endured unimaginable ages and most had decayed and collapsed, leaving only frames or foundations, their former appearance could still be clearly seen:

Mortise and tenon joints, sloped roofs, and simple, ancient decorative lines. These houses weren't scattered randomly but were arranged systematically and regularly along "streets." The streets were also flat, though covered in a thick layer of dust.

They walked along these streets that had been silent for unknown years, shining their flashlights into the empty doors and windows. Inside the houses, traces of stone or ceramic vessels remained, along with structures resembling stoves and areas for resting.

Some larger and more complex buildings appeared to be public buildings, workshops, or storage facilities. Everything pointed to this having once been a planned, organized residential area—a massive underground settlement.

"A... city?" Professor Chen murmured, his voice trembling with excitement and disbelief as he swept his flashlight beam across the continuous decayed buildings. "They built a city... inside the entire mountain?!"

The exploration continued amidst the shock. They passed through silent residential areas, the path beneath their feet sometimes flat and sometimes connecting different levels via short staircases. As they walked, a faint, hollow sound of flowing water reached them.

Following the sound, they arrived at an open space resembling a small plaza.

In the center of the plaza was a stone-built circular pool, its edges carved with patterns that had already become blurred.

In the pool stood a thick stone pillar. The top seemed to have originally been decorated but was now damaged, yet several holes in the middle of the pillar's body allowed clear water to gurgle out and fall into the pool below.

The pool was already overflowing, the water running along a specially carved small stone trough, but it didn't flow far before seeping into the ground through a grid-like stone slab and vanishing.

"It's a water source, a fountain or a public water collection point," Cynthia concluded after observing.

Wei Ziqing crouched down curiously and scooped up a bit of the pool water. It felt cool to the touch, and the water appeared exceptionally clear. This spring water, which had flowed silently for thousands of years, was once one of the life pulses of this underground city.

They didn't stay long, continuing forward. After walking another distance, the surrounding houses gradually thinned out, and the terrain seemed to change slightly. They realized they might be approaching one of the edges of this underground city.

Sure enough, a relatively open area appeared ahead. In the center of that area, right next to the vague shadow they believed to be the "city wall" or the mountain's inner wall, stood something extremely conspicuous—a giant, withered, and lifeless plant.

Its form was quite similar to the glowing plant that had brought them down, also with a thick trunk and distinct branches, but its volume was much larger, like a withered giant tree. Its entire body was a dull, scorched yellow, shriveled and cracked, with no fluorescence emitted, utterly lifeless.

Lu Jianchuan stopped, focusing his flashlight on the withered giant plant, his brow furrowed. "Look at this... doesn't it look like the one we came down on? Only... it's completely dead."

At his suggestion, everyone compared them carefully and found them increasingly similar, as if they were the same species, just on a larger scale and devoid of all life.

"Up there just now, Xiao Wu poured some water on that plant, and it got brighter..." Lu Jianchuan pondered, his gaze sharpening. "If the principle is similar, if this larger one in front of us could 'come alive,' even if just to glow briefly... how large an area could it illuminate?"

This thought sent a jolt through everyone. If they could activate this giant plant, which was clearly in a key position at the city's edge, they might be able to catch a glimpse of the underground city's broader landscape!

"Water! There's water in that pool over there!" Wei Ziqing reacted immediately.

Without needing another word, several of them immediately returned to the nearby fountain pool. They filled their water bottles and even took off their helmets to carry as much clear spring water as possible, then quickly returned to the withered giant plant.

With trepidation and anticipation, they carefully poured the cool spring water onto the giant plant's cracked roots and lower branches.

The spring water seeped in quickly, as if greedily absorbed.

Immediately following that, a shocking change occurred!

The withered, seemingly long-dead body of the giant plant suddenly shuddered!

The dull, scorched yellow receded at a visible rate, replaced by a deep, powerful dark brown that quickly spread toward the tips of the branches.

At the same time, its volume seemed to expand and grow, emitting low creaking sounds as if dormant sinews and bones were stretching.

Even more dazzlingly, from within the trunk and main branches, one point, then two... countless points of brilliant white light shone out from the inside. They rapidly intensified and finally stabilized, forming a continuous and steady massive light source, far brighter and more spectacular than the fluorescence of the plant they had descended on!

The light dispelled the thick darkness, clearly illuminating the city's edge where they stood and a vast area ahead!

"Quick, find a high vantage point!" Professor Chen shouted excitedly.

There was a relatively sturdy and high stone-and-wood structure nearby. Lu Jianchuan and Shen Mingyuan were the first to leap onto its roof, and the others helped each other climb up.

Standing on the roof, they looked around.

Under the brilliant white light of the giant revived plant, a magnificent scene beyond words was suddenly presented before their eyes—

As far as the eye could see were dense, row upon row of ancient rooftops, stretching out along a network of flat streets, clearly layered and neatly partitioned.

Further away were the outlines of even taller buildings of various shapes, possibly palaces, temples, or plazas.

Giant stone pillars, winding staircases, and crisscrossing passages... all of this formed an extremely large and exceptionally complex three-dimensional city system!

Where they stood now was merely an insignificant corner of this giant city sleeping within the mountain's belly.

The city's edges appeared faintly in the light, while further areas merged back into the darkness, suggesting its scale was far beyond what was currently visible.

This was not just scattered ruins in a natural cave, but a meticulously planned and thoroughly constructed underground kingdom.