In the sprawling urban ruins before them, it was nearly impossible to see any building fragments taller than two meters.

Other city ruins at least had towering structures, but here, there was nothing but shattered rubble and black ash.

The fractured overpass Shen Feng and his companion stood on was part of the old city’s periphery, which was why it had managed to survive, more or less.

As far as the eye could see, there were no fewer than seven massive nuclear craters within their field of vision.

And that wasn’t even counting the smaller ones.

Each of these massive craters was about the same size as the one Shen Feng had entered when he first arrived in this wasteland world.

The bottoms of the craters were lined with shimmering, vitrified glass. Even from this distance, Shen Feng felt he could sense the horrifying radiation emanating from them.

Standing in one without a hazmat suit would likely mean death within minutes from organ failure and massive internal hemorrhaging.

Even out here, the Geiger counter’s reading had already spiked to over five hundred microsieverts.

Even though he was bundled up tightly in his clothes, wearing both a face shield and a mask, Shen Feng still felt immense psychological pressure, as if something were silently carving the flesh from his body.

"How are we supposed to get in?" he asked Firefly.

The legendary Iron Country couldn’t possibly be situated amidst these highly irradiated ruins.

Firefly sighed, as if lost in a flood of memories, then said:

"Follow me."

Carrying their weapons, ammunition, and food supplies, the two climbed down from the overpass to the ground level.

Firefly led Shen Feng swiftly through patches of blackened ruins until they reached a spot concealed by the wreckage of abandoned cars.

The beeping from the Geiger counter subsided a little.

Firefly scanned their surroundings, seemingly trying to recall something, before crawling under a car and vanishing from sight.

Startled, Shen Feng immediately crawled under the car after her.

He quickly discovered a hole beneath the vehicle, just large enough for one person to pass through. The metal plate that had once covered it was now set aside.

Shen Feng immediately crawled inside.

The tunnel was a good twenty or thirty meters long. After crawling for some time, the space ahead of Shen Feng suddenly opened up, and he dropped onto solid ground.

A wave of damp air washed over him. It was pitch-black. Just as Shen Feng was about to speak, he felt a soft hand grasp his own. Firefly’s voice followed, a soft whisper:

"Don’t speak. You’ll adjust in a moment."

Shen Feng’s eyes gradually adjusted to the darkness. He soon began to perceive a faint glow emanating from the surrounding walls, allowing him to make out the contours of their surroundings.

But that was the extent of it.

The glowing substance appeared to be a type of subterranean, phosphorescent moss.

Shen Feng ran a hand along the nearby walls. They were rough, bearing crude tooling marks, as if they had been constructed in a hurry and never finished.

’Where is this place?’

"This is the Iron Country," Firefly whispered.

"I haven’t been back for a year or two, so it may have been expanded... Many tribes live down here. We must be careful and get to the central region as quickly as possible to find the Nation of 0."

Shen Feng was left speechless.

He never would have imagined that the so-called Iron Country was actually a subterranean settlement!

There was no natural light here whatsoever—only the faint glow from the walls, which was just enough to reveal the barest of outlines.

The many areas without the glowing moss were plunged in absolute darkness, like black holes.

By now, Firefly’s pupils had constricted into thin, vertical slits that seemed to emit a faint glow of their own. She was clearly accustomed to this environment.

"The pathways here are extremely complex; even I don’t know them all. You’re not adapted to this environment, so you have to stick close to me. If you fall into one of those Abyss pits, you’ll never get out!"

Shen Feng nodded, pulled a pair of night-vision goggles from his backpack, and put them on. The darkness that had enveloped him immediately gave way to a much clearer view. In a low voice, he said:

"Let’s go." 𝑓𝘳𝑒𝑒𝓌𝘦𝘣𝘯ℴ𝑣𝘦𝑙.𝘤𝑜𝑚

Firefly glanced at his night-vision goggles with curiosity, understanding this was undoubtedly another treasure in Shen Feng’s possession.

The two walked on in silence through the dark, subterranean space. The world around them was still, with only the sound of their own footsteps breaking the quiet.

Gradually, however, other sounds emerged: the squirming of earthworms in the soil, the scuttling of mole crickets across the ground, the dripping of water, and more.

They even began to hear what sounded like faint whispers, as if people were murmuring just out of sight.

This subterranean world was far more bustling than they had imagined.

"That’s just people talking far away. The sound travels through the tunnels and becomes a muddled whisper by the time it reaches us," Firefly explained quietly in Shen Feng’s ear.

Her voice was hushed, as if she were afraid of being overheard.

Shen Feng nodded in understanding.

They continued on for about a kilometer before Firefly led Shen Feng down a different path, this time into a downward-sloping tunnel.

After about ten meters, they emerged into a new, horizontal passageway.

Here, the ground was solid and level. The pitch-black corridor stretching out before them was like a silent behemoth, waiting to devour all who dared enter.

Shen Feng scanned the walls around them when suddenly, behind a patch of fluorescent moss, he spotted some words:

"Songjiang New City."

Shen Feng froze as if struck by lightning. He finally understood where they were.

This wasn’t some hastily constructed underground Shelter. It was the old subway system of the Old Demon City!

They were in the subway!

The Iron Country was a kingdom within the subway!

Looking down from the platform, Shen Feng immediately saw two railway tracks snaking into the distance.

During the summer vacation after his first year of high school, he had joined a school study tour to Demon City. He had visited the science museum and even ridden the subway.

But he had a nagging feeling that this subway wasn’t exactly the same as the one he remembered.

The space seemed vaster, the ceilings much higher.

Moreover, the path Firefly had led him down earlier was clearly not part of the original subway system, but looked as if it had been dug out later.

’Could the Old Demon City’s subway system have been under continuous construction even after the war broke out?’

Lost in thought, Shen Feng followed Firefly into the empty subway tunnel.

They tried to muffle their footsteps, but the sound still echoed, seeming jarringly loud.

After all, everything else was just too quiet.

Shen Feng looked around, almost feeling as if they were the only two living beings in the enormous subterranean space.

Soon, they had passed two former station platforms and arrived at a new one.

"Careful." Shen Feng’s brow furrowed. He grabbed Firefly’s hand. "Something’s not right here... It sounds like... a lot of footsteps..."

But when he scanned the area, he could only see the gray walls and vaulted ceiling, no other living creatures.

Hearing his words, Firefly’s expression changed drastically. "This is bad," she said urgently. "We have to go back. This might be a death nest!"

The words had barely left her mouth when the gray walls and ceiling began to writhe.

The walls then seemed to come alive, shuddering violently as countless blood-red pinpoints of light flared into existence.

Through his night-vision goggles, Shen Feng could see it all with perfect clarity.

Rats. Thousands upon thousands of rats.