Xu Xin walked up to the heavy iron door.
The design of the iron door was like the door to a gold vault, and he was now inside the door.
Xu Xin had seen the way the door to vaults opened in movies and games. It was always by turning the disc that was like a steering wheel outside the door. Then, after a deflating sound, the circular door would move out and move to the left or right.
However, he was in the room and there were no disc-like devices. He could only try to push the door with his hands.
"Screech---" The ear-piercing sound of metals rubbing against each other was heard. Under Xu Xin's full efforts, the door budged slowly.
"It works!" Seeing the door being pushed open, he was overjoyed and continued to push.
"Crack!" With a crisp sound, the round iron door was left the door frame, leaving a gap of two fingers wide between the door and the frame.
Xu Xin didn't rush to open the door. Instead, he peeked through the gap.
He had thought that it would be a modern room like a vault, but to his surprise, what he saw through the crack was a wall made of pale red soil, as if he had entered another cave.
"There's another cave outside?" Xu Xin was confused.
Didn't that mean that there was just a square metal room buried underground that looked like a gold vault, and a European from his world had died in the room in the 1980s?
It was just strange.
"Cocoa, is it dangerous outside... What are you doing?!" Xu Xin's eyes twitched as he looked at Cocoa, who was lying on the ground and scratching at the skull with its claws.
The poor skull was being rolled around on the ground like a ball by Cocoa. It slapped it left and right, creating a very strange scene. A cute red panda was playing with a skull.
"Yin?" Cocoa looked at Xu Xin in confusion.
Right, Cocoa is a red panda, so he can't expect it to be afraid of human skulls. Xu Xin shook his head helplessly, "I'll have to give you a good bath after we get out!"
"Yin!"
However, the little fellow's antics had caused his inexplicable fear of the skeleton to dissipate quite a bit.
"Cocoa, is it dangerous outside?"
"Yin," Cocoa shook its head, indicating that it did not sense any danger.
Xu Xin took a deep breath, reached his fingers into the gap, and pulled the door to the side.
With an ear-piercing sound, the door was slowly opened halfway.
Xu Xin then stopped. As long as the gap was enough for him to pass, it would be fine.
He passed through the door and looked outside.
Xu Xin was stunned by what he saw. He rubbed his eyes and looked again.
He had thought that this was a cave, but he was wrong, very wrong.
"Yin!" Even Cocoa let out a cry of surprise.
He subconsciously took two steps forward, then abruptly stopped.
He suddenly found himself on the edge of a cliff.
That's right, it was the edge of the cliff.
Fine rocks and dirt rolled down from the cliff. Xu Xin looked down and could not help but clench his jaw. His facial muscles twitched and beads of sweat rolled down his forehead.
Below the cliff, almost a thousand meters deep, was a huge underground world that seemed to have no end.
With the enhancement of his night vision, he saw everything in the underground world.
"Is... Is this real...?" Xu Xin's lips trembled as he stared at the scene before him.
He saw countless green and blood-red vines dancing wildly below.
He saw a giant man-eating flower with its bloody mouth open and devouring an animal that looked like a dinosaur.
He saw a giant monster that was tens of meters tall and covered in green seaweed tearing off the blood-red vines and stuffing them into its mouth.
He saw countless flying insects the size of cars with their tails shining with a dazzling light, flying around the man-eating flower.
It was as if a group of demons was dancing wildly.
The scene in front of him was too unreal, and the amount of information was too huge, he was just frozen.
He looked around in a daze.
At this moment, he was in a mountain cave at the top of the underground world. The top of the underground world was right above his head. He could touch it by stretching out his hand.
If the underground world was a huge room, he was a small bug in the gap between the ceiling and the light cover. He was looking down at the huge room, and the monsters were the owners of the room.
The dense red dots on the map made him feel a sense of fear and despair.
[Congratulations, you have discovered one of the hidden secrets behind this world and become the first survivor to discover the underground world. The reward will be given after the end of this jungle exploration event.]
[Survivor, please do not share the secrets of the world with those who do not know the secrets. Otherwise, you will be severely punished.]
[Don't panic. The underground world isn't something that the current survivors can deal with. How to deal with the beast riot is what the current survivors need to consider.]
[Survivor, please continue to work hard, strengthen yourself, and work hard to survive in this world.]
[Another warm reminder, never abandon your treehouse. It's the only thing you can rely on.]
The mysterious voice rang in his ears once again, causing him to snap back to his senses.
With these monsters as a foil, he actually felt that the mysterious voice was so friendly.
"Wait a minute! Where is this place? Why is there such a large space underground, and why are there so many monsters?!" Xu Xin asked the question that he wanted to ask the most.
[The secrets of the world must be explored by the survivors themselves.]
The mysterious voice only answered him with this one sentence. No matter how he asked, it did not speak again.
At this moment, Cocoa had already burrowed into Xu Xin's arms. It buried its head in his chest and trembled.
There were simply too many monsters down there. Even at a depth of a thousand meters, Xu Xin could still feel the pressure from the huge monsters, let alone Cocoa.
Fortunately, the mysterious voice also said that they didn't need to deal with these huge monsters now. They just had to think about how to deal with the beast riot first. In other words, these monsters wouldn't come out now. It was equivalent to him knowing the contents of the later versions in advance.
This made Xu Xin heave a sigh of relief.
He suddenly thought of something, "Cocoa, didn't you say that the treasure chest is here? Don't tell me the golden treasure chest is down there?"
He had to first find the golden treasure chest. Xu Xin tried to calm himself down and rubbed the little guy's head.
"Yin!" Cocoa also suddenly recalled this matter. It jumped out of Xu Xin's arms and tugged at his trousers, indicating for him to follow her.
There was more than just a small cave on the cliff outside the giant circular iron door. There were other holes in the walls of the cave, but Xu Xin had been so shocked that he did not notice them.
Following Cocoa, Xu Xin quickly reached the end and saw the golden treasure chest.
Even in the dark underground world, the treasure chest was still emitting a faint golden light, illuminating the surroundings at the end of the cave.
Xu Xin looked at the treasure chest. He first confirmed the patterns on the chest. It was indeed the head of a beast, but it was different from the kylin he had in mind. It seemed that the three treasure chests were not printed with a kylin.
He decided to open the chest here.
He took out the key, inserted it into the golden treasure chest's keyhole, and twisted it. A mechanical sound was heard, and the treasure chest was opened.
"Yin!" Cocoa climbed to the edge of the golden treasure chest and looked inside as well.
There was a bottle of gray medicine and a thin card in the golden treasure chest.