The vertical square passage is 2 meters long and wide, with smooth walls and nothing inside.

Nie Tian asked everyone to hold on to the rope, and one person rappelled first, passing through a passage about 5 meters deep, and arrived at the tunnel on the lower floor to investigate.

In the lower tunnel, the air is thinner than the upper level, and the inside is damp, and the walls are covered with moss.

And it is even shorter and narrower, only allowing one person to pass through, and it is a little difficult to turn around inside, which makes people cramped and uneasy.

The tunnel is open in front and back, and I don't know where it leads.

Nie Tian thought for a short time and had an answer.

I wanted to use water to see the tunnel up and down, but now that the road ahead is unknown, I decided to save water in case of emergency.

Nie Tian suddenly remembered a function on his mobile phone, took out his mobile phone, turned on the gyroscope, and tested the level of the ground in one direction and multiple points in the tunnel to find the downward direction of the tunnel.

After listening carefully for a while, the sound in the tunnel was not abnormal, and then he beckoned his classmates to come down.

At this time, the team members had already fixed the ropes and came down one by one, Nie Tian instructed the classmates behind him to follow him closely, and then asked him to pass the words to the classmates behind, just like that, one by one, until the last classmate.

The tall team members are all hunched over and hooked backs; The short team members also instinctively raised their bodies.

There are a few players who are sensitive to enclosed spaces, pulling the backpacks of the players in front of them, enduring fear and oppression, and struggling.

There are also some female team members, in order to relieve the pressure, the front hand and the back hand, connected in a string, and slowly rubbed their steps forward.

In the tunnel, the team members stumbled and groped for the raised stones under their feet, moving slowly, unable to distinguish the direction, and could only feel that they were turning left and right in it, and after thirty minutes, Nie Tian stepped on the iron grating plate more than one person wide and stopped.

Nie Tian stomped lightly a few times, testing the sturdiness of the iron grating plate, and heard a slight cracking sound at the joint, judging that the grating plate was fixed with screws from below, and it had been loosened.

Then he took a step back and stomped down suddenly, and in an instant, the sound of metal collision was like a thunderbolt echoing in the tunnel on a sunny day, impacting everyone's sensitive nerves and making them tremble.

The iron grille plate fell below in response, Nie Tian leaned over to observe the situation below, and then said hello to the team members behind, crossed his hands on his chest, and jumped straight into the passage more than 3 meters high.

With the momentum of the fall, it fell heavily on the iron grating plate at the lower entrance of the passage, and kicked hard, like a bamboo, and the two overlapping iron grating plates fell to the next layer with the sound of metal impact.

Nie Tian used his hands and two forearms to support the cave wall at the moment when the iron grille plate fell, and after sliding for a distance, he stopped in the passage.

Then I used my feet to prop up the wall of the cave, adjusted my body posture, looked down, observed for a while, and roughly judged that the height was less than 3 meters from below.

Immediately, the hands and feet loosened at the same time, and fell lightly.

Nie Tian stood firmly, looked around, and made sure that this was the real tunnel, the ground was paved with cement, the size of a normal corridor, and the tunnel where it was originally located should be a ventilation duct.

After probing around for a while, to make sure there was no danger, he shouted to the team above, "You can come down." ”

The team members knotted the ropes and came down one after another, and everyone who had just arrived on the ground breathed a sigh of relief, relieving the depression of the airway above.

Until the 48 students arrived, Nie Tian said to the team members who were sitting on both sides of the tunnel: "You guys are resting here now, and I'll go and scout the surrounding environment."

You should never act alone, even if you go to the toilet, you must accompany you.

And you can't go far, the tunnels here are intricate, and it's easy to get lost. ”

Nie Tian went deep into the tunnel, and there was a 30-centimeter-thick steel door at intervals.

These steel doors, manufactured as needed, are bulletproof, poison-proof, and waterproof, allowing each section of tunnel to form a completely independent high-strength, extremely safe space.

Luckily, these steel doors have a stick-shaped switch handle on both sides of the front and back, allowing the door to be opened on either side.

Nie Tian opened the steel doors one by one and walked through the tunnel.

From time to time, there were holes of different sizes on both sides of the tunnel, and Nie Tian entered one at random, and found that there were holes in the holes, and the holes were connected, twists and turns, intricate, like a labyrinth.

Nie Tian didn't dare to be careless, so he stopped and returned to the tunnel in time to continue to explore along the tunnel.

Finally, when we were about to reach the end, we found a basement labeled "Temporary Break Room".

Nie Tian opened the door and stood in the doorway to look inside, there was nothing but a long table made of old-fashioned solid wood and ten chairs.

Just as he was about to close the door, Nie Tian suddenly felt that something was wrong, and looked around the room again, but still didn't find a problem, so he simply walked into the room and searched carefully, but still didn't find anything valuable.

Nie Tian's instinct told him that there must be something here, but he hadn't discovered it yet.

He walked out the door again, closed it, and closed his eyes as he remembered all the images that had just fallen into his eyes.

After a while, his eyes suddenly opened, and there was a faint golden light flashing inside, and he looked at the sign at the gate, and found that the paint on the surface of the sign was a little peeling, and he gently picked it with his fingernails, oxidizing the brittle paint, and instantly peeled off and fell off a piece.

After a while, Nie Tian cleaned off the upper layer of paint, and the "Construction Headquarters" appeared below.

Looking at the paint handwriting, Nie Tian was sure that his instinct was right, there must be something in it that could be used.

Re-entering the basement, Nie Tian caressed the flat walls while carefully observing every detail, hoping to find clues.

Walking along the four walls, Nie Tian felt that the wall facing the door felt thicker than the other walls, and stepped forward.

Scraping a white ash with a dagger, the situation he imagined, did not appear.

Nie Tian looked at the wall, thought for a moment, and scraped another white ash in the middle position.

Then he smiled, and the movements of his hands were a little faster, gently peeling off the top layer of white ash one by one.

Just as Nie Tian was busy peeling off the wall, the team members lined up in two rows, leaning against the wall of the tunnel, some huddled and whispered, some were sad alone, and some sobbed softly......

At the other end of the tunnel, one tall and one short, two phantoms glowing with a cyan glow, wearing pointed hats and strange comical robes, slowly came to the procession.

The one who came was the "babbling two handsome".

They stood in the middle of the tunnel, looking greedily at the crowd, while the team had no one to see or hear them.

Ya Shuai shook his short and fat phantom body, with bursts of fat waves, licked his mouth, and said in a hoarse voice like an old duck: "Ya Ya Ya! It's so delicious! ”

He Shuai pressed the fat body that shook up and down with Ya Shuai, and made a sharp and piercing, crying wolf-like sound, and said in a strange voice: "Hey~ When can I have a little bit of interest, I will be excited when I see food!" ”