It took less than ten minutes to open a passage, as destruction is always more efficient than construction. Zhang Haike and his companions entered in single file, lighting torches. Once they passed through the brick wall, they found the situation here was completely different from what they had imagined.

First, there was mud. Behind the brick wall was a vast stone hall; except for the side they entered, which was made of bricks, the rest was composed of large stone slabs, but it was unclear what material the stones were made of. The entire hall was filled with mud, and there was a very sloped stone ledge around the perimeter that they could walk on, where a corpse was sitting.

As they entered and pushed the corpse, it fell into the mud. Zhang Haike helped it up and discovered that the joints of the corpse could still move. It was dressed in early Republican clothing and had its legs bound. He initially wanted to examine the corpse closely but quickly dismissed the idea when he realized that the massive mud pool was filled with such corpses.

From the state of the corpses, it was impossible to tell how deep the mud was; some were submerged up to their heads, while others were only waist-deep in mud. The mud was green and extremely viscous, making one feel nauseous.

They walked along the edge of the stones and, after a circuit, found that there were no other passages leading to different areas within the stone hall.

“Is this all there is?” one person muttered to himself.

Zhang Haike replied, “The submerged parts of the people on the sides are higher, while the ones in the middle are lower. This mud pool is shaped like a funnel; there should be openings beneath the mud leading to other places.”

“Damn it.”

“The corpses in the mud are all wearing goggles and protective masks. Even if there are no openings, they were still trying to retrieve things inside. But I tend to believe there is a passage,” Zhang Haike said. “Because everyone is tied with ropes, and our earlier judgment was wrong. This opening wasn’t sealed off by people from the outside; it was sealed from the inside by these people. Look, the sealing marks are all on the inside. These people sealed themselves in.”

“Are you saying that there must be something suspicious in this mud? They didn’t want it to rise up and harm others, so they sacrificed themselves?”

“I never think of people in our line of work as being that noble. The ground outside has bricks, which indicates that the people inside are constantly blocking it while someone outside is trying to dig in. I don’t know the specifics, but we need to send someone to keep watch at the opening. It should be safe inside.”

“No one would dig through a brick wall like the Zhang family does. They hammer the bricks into the wall while we are the only ones digging outwards. Stop talking nonsense.”

“I’m not talking nonsense.” Zhang Haike suddenly took a breath, pulled out the pocket watch again, and opened it to show them the photo. “Do you know who this person is?”

Several people looked at each other and shook their heads. Zhang Haike glanced at the hole they had come through and said, “This person is the father of the little ghost. I saw him when I was a child.”

He lifted a corpse and brought the torch close to its grotesque face, saying, “Take a good look at the faces and hands of these corpses; they all belong to the Zhang family and share the characteristics of the Zhang family.”

“Ah?” The others hurried to look, and upon seeing the fingers of the corpse, they were shocked to find them extraordinarily long, turning pale instantly.

“What is going on here?”

Sure, here’s the translation of the provided text:

“I know that the little ghost’s father is dead, but the family is very secretive about these deaths. We might have been deceived this time; someone arranged for us to come here.”
“Who?”
Zhang Haike turned around: “It’s that little ghost. We were led here all the way; think back, almost all the information was provided by him.” He paused and continued, “This kid lured us all here. Is it for his father’s corpse?”
“Damn it, I’m going to go up and twist his neck.” One of them was furious. Zhang Haike immediately waved his hand: “Wait a minute, the deaths of these Zhang family members are too suspicious. That little ghost probably doesn’t want to harm us; he wants us to see how these people died. He might just want to find out how his father died.”
“No.” Another person said, “Come look here.”
Several people turned their heads and saw that the man had jumped into the mud and was carrying another corpse. He twisted the head of the corpse with force, and in an instant, the head came off easily.
“The neck is broken, and these corpses have many injuries.” He said, “There was a fight here, and it was done in the way the Zhang family kills. Some of these people were murdered, and the ones who killed them were also from the Zhang family. This is a scene of internal strife within our family.”
Several people looked at each other. In fact, everyone knew a little about the internal strife, but seeing such a scene, these kids were still a bit unable to digest it.
“The little ghost’s father was murdered by our own people?” One of them became fearful, “Damn it, his father is dead, and our fathers are still alive. Could it be that our fathers are the murderers? Is this little brat trying to lure us here for revenge?”
The group exchanged glances, paused for a moment, and immediately rushed towards the exit. As they reached the entrance, they saw the muffled oil bottle squatting behind the brick wall at the entrance, silently watching them.
Several people slammed to a stop, and the last person fell into the mud. The others stood still and began to shiver. One of them said, “Little ghost, why did you come down?”
The muffled oil bottle looked left and right, then looked at them. Zhang Haike remained relatively calm; after a few minutes of stalemate, he reacted and asked, “You heard our discussion just now, right?”
The muffled oil bottle nodded.
“Is it just as we speculated?”
The muffled oil bottle looked at him and said, “It’s not speculation. I was there when all this happened.”
The group looked at each other again: “Did our father really kill your father?”
“I don’t even know who your father is.” The muffled oil bottle said, “The father you think is mine isn’t actually my father.”
“Then why did you lure us here?”
The muffled oil bottle looked at Zhang Haike and said, “I need to come to this place. I’m too young; there are many things I can’t do.”
“What do you need to come here for?”

“Has nothing to do with you,” the muffled oil bottle said. “Beneath this swamp, there are passageways like spider webs, all filled with silt. However, each passageway connects to various rooms where you can rest and breathe. Some of these rooms contain many things you need. With the equipment from these dead people, if you advance four or five rooms, you can complete the trial.”

“And you?”

“I need to go much deeper,” the muffled oil bottle replied.

“What exactly is this place?”

“It’s a long story. This is the site of the ancient city of Sizhou, buried under at least four layers of rock beneath our feet; we are only on the first layer. The Zhang family has been managing this ancient city. It disappeared and was buried in silt due to a flood, so there are many treasures inside.” The muffled oil bottle continued, “The things I want are in the deepest part.”

“Do you not need help?” After the muffled oil bottle finished speaking, Zhang Haike asked.

“You can’t help me,” the muffled oil bottle said. “You know nothing about this place. Take what you can and leave quickly, or else danger will not just come from here. If the Zhang family finds out you came here, you won’t have a good ending either.”

Zhang Haike and the others exchanged glances. The muffled oil bottle said, “I didn’t want to say this. I wanted you to experience failure on your own, but you are too persistent and clever, and you actually made it down here. Now, I’ve said what I needed to say; whether you believe it or not is up to you.” With that, the muffled oil bottle jumped into the silt and disappeared.

The others watched as a few bubbles surfaced from the silt, floundered for a moment, and then the muffled oil bottle was gone again, leaving them exchanging glances once more.

“What now?” one of them said. “Is what that kid said true?”

“Whether it’s true or not doesn’t matter. If we listen to him, it would mean we’ve lost to this little brat. We’ve already lost enough face; I can’t swallow that. Why should we listen to him?” another person said.

After a moment of silence, one of them cursed, gathered his gear, and jumped down suddenly.

Zhang Haike watched as they all jumped in one by one, feeling a particularly bad premonition rise in his heart, but he still followed them into the silt, diving down.

The feeling of sinking into the silt was very strange. Zhang Haike didn’t elaborate much; he only mentioned that he held his breath for about three minutes before he felt a rope guiding him to the side of a passageway. He grabbed the rope with one hand and felt along the edge of the passageway with the other, moving forward until he discovered a well opening. The well was filled with silt, and the ground was paved with cobblestones, where several mud monkeys lay gasping for air.

It seemed like a family’s courtyard, which had clearly sunk underground to become a cave, but the bonsai, rockery, and cobblestone ground still remained.

Torches had already been lit. Without further judgment, one might think it was a very small stone hall, where the flood had collapsed two houses, and the outer walls had fallen onto the courtyard, now serving as a slanted ceiling. Zhang Haike wiped the black mud off his face and, aside from the few of them, he did not see the muffled oil bottle.

“Where’s that kid?”

One of the people pointed to the side, and they saw a muddy footprint on the ground leading into a dark area where the torchlight couldn’t reach. Zhang Haike wanted to follow immediately but was pulled back by someone: “That kid told us not to follow him, or it would be very dangerous. He said that path is one only he can take.”

Zhang Haike, feeling impatient, thought to himself that this kid was really reckless, refusing help. This was typical behavior for a child. He said, “After all, he is our kin. No matter what his intentions are, we can’t let him go to his death.”

Zhang Haike followed the muddy footprints, and a few others went along with him. They soon discovered a hole in the corner of the wall, leading to another gap.

Zhang Haike remarked that the ancient city was completely buried in silt. In some areas, the silt had completely turned to soil after such a long time, while in others, it remained viscous. Only in many larger, enclosed ruins of ancient buildings was there any air left. The earlier explorations by the Zhang family had established pathways between the traversable routes, hiding ropes in the silt that could be felt as long as one entered the mud, allowing them to reach another room before suffocating. In some cases, the distance between rooms was too far, and the previous explorers had resorted to digging theft tunnels to advance. In short, due to the complex geological conditions in the ancient city, it had become a system composed of theft tunnels, ropes hidden in the silt, and various passages.

The Zhang family’s ancestors had initially used a networked exploration method, but in the later stages, all routes converged into one, clearly indicating a focused purpose. This was because, at the beginning, their aim was merely to collect valuables, but later, they discovered a secret among the treasures they had gathered, which shifted their focus to exploring this secret.

In the corner of that room was an entrance to a corridor. After entering, they found themselves in a dry ancient ruin that had collapsed halfway. They could see a ceiling that looked like it had been cut with a knife, with half of it buried in the soil, causing the entire roof to tilt.

This was a side room next to a garden, suggesting it belonged to a wealthy family, as the house was quite sturdy. Although it had collapsed in a flood, many of its shapes had been preserved.

There, they saw two forks in the road, with the tomb passage continuing forward, splitting into two paths. From the traces in the silt, it was easy to discern which path the “Dumb Oil Bottle” had taken, but Zhang Haike realized they couldn’t follow him any further.

This was because one of the theft tunnel entrances was large, while the other was small. The large one was of normal size, but the small one could only accommodate someone the size of the “Dumb Oil Bottle.” Although they were slightly larger than him, they definitely couldn’t squeeze in.

Zhang Haike was puzzled, and after carefully examining the small theft tunnel, he discovered that this was a last resort. Surrounding the tunnel were four slabs of blue stone in the soil, indicating it was a drainage passage, with a fixed diameter that couldn’t be expanded.

No wonder the “Dumb Oil Bottle” said only he could pass through.