Sitting ten meters away from the entrance, Xu Xin held Cocoa in his arms as he waited for the red gas to dissipate.
It wasn't that he didn't want to go in, but the smell was simply not something that a person could bear.
He was also worried that the smell was poisonous. Although he didn't feel anything wrong with his body other than just feeling a little weak after throwing up his dinner, he didn't know if it would cause any serious damage to his body if he inhaled too much of it.
It was better to be cautious.
Gradually, no more red gas came out of the hole, and the red color around also drifted away with the wind.
Xu Xin walked to the entrance of the cave and looked inside. There was still a faint red gas floating in the cave, but it was very thin, much better than when it had just started pervading the air.
The cave wasn't ventilated, after all, and it was unrealistic to wait for the gas to dissipate completely. This was the best result. Xu Xin sighed and asked Cocoa, "Are you still going down with me?"
Cocoa's body stiffened. After a moment of hesitation, it nodded its head and jumped onto his shoulder.
This little fellow. Xu Xin patted its head and tied his clothes to his face, then gritted his teeth and entered the cave.
Faint red gas was floating in the tunnel in the cave, but to Xu Xin's surprise, he found that the red gas did not fill the entire tunnel. It was only floating in the upper part of the cave.
He bent down, and sure enough, although the air at a lower altitude still carried that strange stench, it was already within the range that he could bear.
"It seems that this strange gas is lighter than air. That's great then. The stinky gas in the iron door should have already dissipated!" Xu Xin walked through the tunnel while bent over, swiftly reaching the opened underground iron door.
Looking inside, there was a square iron passage that went down and could only fit one person. An iron ladder was fixed on the wall of the passage, which went down for an unknown depth.
The ladder was covered in rust. Xu Xin felt quite fearful when looking at the passage, but he still stepped on the ladder and began to climb down.
The passageway was very long, and he climbed down step by step. The only sounds in the tunnel that was like an underground well were his footsteps and the occasional cries of Cocoa on his shoulder.
The little guy was afraid too. It clutched the clothes on his shoulders tightly, afraid that it would fall off.
"Isn't this too long?! Don't tell me I'm really underground!"
The tunnel was so long that Xu Xin could feel his arms trembling from exhaustion. But he had no choice. He was already halfway down, and he couldn't just give up and climb up again.
He continued to climb down.
After God knows how long, just when Xu Xin felt like he could no longer hold on to the ladder, he finally entered a room.
After climbing down for another four to five meters, Xu Xin finally stepped onto the ground.
"I've finally made it!" He stood on the ground and massaged the muscles on his arms with his hands crossed, "How much iron was used to make such a long ladder?!"
As he mumbled, he turned around. Xu Xin began to look around. However, the first thing he saw made his pupils constrict as he gasped.
The entire room was empty. Three of the four walls were standard iron plates, and there was not even a window. There was only one wall with a door that looked very thick and solid. The door was round, a little like the door of a gold vault.
The first thing he saw was a human-shaped skeleton in old clothes leaning against the wall.
"Someone has been here before!" Xu Xin was shocked. In the depths of the wilderness, not only was there an underground room that looked like a gold vault, but there was also a skeleton in the room!
Who was he? Could he be a former survivor? Or was he the native of this world?
Xu Xin looked at his clothes carefully. Even though the skeleton's clothes were in tatters for some reason, he could still tell that it was a standard wilderness survival outfit.
Going closer, Xu Xin saw a dirty bag beside the skeleton. The bag was made of animal skin. It was unknown how long it had been underground, but most of the skin had fallen off, and it looked extremely old.
"Sorry for disturbing you, brother," Xu Xin muttered in his heart as he opened the bag.
There was a moldy smell in the animal skin bag.
The things inside were quite messy. Xu Xin poured everything out and began to go through what was inside.
"A multi-purpose knife that's completely rusted and has fallen apart, an empty lighter, and a small flashlight. These are all tools from Earth! This person must have come to survive in the wilderness. He has such a complete set of tools," Xu Xin mumbled to himself, "But the question is, why would someone bring a tool from Earth to this world?"
Cocoa jumped down from his shoulder and used its little paws to rummage through the items.
There were even empty packages of compressed biscuits inside.
He picked up the lighter and flashlight. Although the words on them were blurry and the surface of the flashlight was cracked, Xu Xin could still see the name and logo engraved on the surface of the product. They were in words that he could not understand.
He had come into contact with European languages before, and the letter should be Greek.
He picked up the packaging of the compressed biscuits again. Although he still couldn't understand the words on the packaging, he could vaguely see the production date on it. It was April 1980.
The shelf life of ordinary compressed biscuits was about three years. If this person was not eating compressed biscuits that had passed their shelf life, it meant that he had been dead for at least 40 years!
Someone had already arrived in this world 40 years ago!
When the moon in this world had changed from a full moon to a new moon in one day, and it was much larger than the moon in his original world, he knew that this was definitely not his original world. Even now that he saw the goods from Earth, he still did not change his mind.
Xu Xin felt a chill run down his spine. What kind of secret was this world hiding?
Could it be that someone had already been sent to this world forty years ago? But how did the other party bring things from Earth here?
Looking around the room again, the more Xu Xin looked at it, the more he felt that it was like a prison.
However, even in a prison, there would be a toilet and a bed, but this place was empty. Other than the skeleton in tattered clothes, there was only a seemingly very heavy iron door and a vent-like passage above his head.
There was no diary in the animal skin bag for Xu Xin to refer to. He took another look at the skeleton. Other than the tattered clothes, there was nothing of value which disappointed him.
Come to think of it, who would write a diary anyway?
"Yin!" Cocoa suddenly cried out as it looked at the metal wall behind the skeleton.
"What's wrong?" Xu Xin followed Cocoa's gaze.
There seemed to be some words carved on the metal wall behind the skeleton, but they were blocked by the skeleton, only revealing a little trace.
Xu Xin gently moved the skeleton.
However, with just a slight push, the skeleton fell to the ground. Its bones fell apart and scattered all over the ground. Xu Xin jumped back in shock.
After the skull fell to the ground, it rolled on the metal ground and returned to Xu Xin's sight. The skull was facing Xu Xin, and its deep eye sockets seemed to be staring straight at him.
"Hii----!" Xu Xin gasped.
In the past, he did not believe in ghosts and gods at all, and he was not afraid of skeletons. However, ever since he came to this world, his world view had somewhat collapsed.
At the very least, the science that he knew could not explain why he had come to this world after he came to, why plants grew so quickly, and why eating fruits could give him special abilities.
In this world, anything could happen, including the sudden resurrection of this skeleton.
However, it didn't come to life. It only looked like it was staring at him.
The iron house was very quiet. Xu Xin endured the strange feeling in his heart and looked at the wall that was uncovered.
There was a string of words carved on it, probably carved with a knife. There were also purple-black stains on the side, which looked like dried blood.
But what made Xu Xin speechless was that the words carved on the wall were the same as the words on the flashlight and the compressed biscuits. They were all strange letters.
Xu Xin had only learned English and some Spanish before. He couldn't understand any other European languages, let alone Greek, the second most difficult language in the world.
"Yin?" Cocoa tilted its head and looked at the words on the wall. Unable to understand anything, it looked away and turned to the skull on the ground.
"This is too hard to bear. I found a clue but I can't understand it," Xu Xin sighed and looked at the heavy door.
Whether or not he would gain anything from this underground exploration would depend on what was behind the door.