"Navigation beacon," Zhou Qi said calmly.

"The navigation standards are ready," the soldier replied.

Soldiers set up a signal tower more than one person tall next to the drilling platform. The red and blue lights on the tower flashed alternately, just like the lighthouse that once guided the way home in the air force base.

But this is not an ordinary signal tower, but an underwater sound propagation device equipped with hfg-091 electroacoustic conversion and signal processor.

The base array, electronic cabinet and auxiliary equipment are all integrated into this signal tower.

At the same time, when Zhou Qi entered the underground river, he would also carry a suitcase-sized active sonar device to receive the coordinates of the signal tower.

The propagation efficiency of underwater electromagnetic waves is very low, so when Qingshi was thinking about how to transmit information underwater, sonar equipment became the most critical tool.

The most important significance of it is that when it completes its mission, it will use it to find a way back.

The huge maze of groundwater roads is complicated and humans will lose their way without realizing it.

Zhou Qi also needs such a reference object to determine his own position.

Zhou Qi is a water supernatural person, and he can even breathe through his skin underwater, just like a real frogman.

But he also has his limits. When his mental and will dry up, Zhou Qi must return to the normal way to survive. At that time, he needs to use his mouth and nose to absorb oxygen again.

In the past, Zhou Qi rarely ventured into underground river basins with unclear terrain because it was too dangerous.

According to Zhou Qi's own estimate, his own mental power can support him in only two hours of time.

Therefore, he must have a way out, otherwise he may stay in the underground river forever.

"Elevate the martial law level," Zhou Qi said: "Everyone, keep here, my retreat is in your hands. Check the time, if I don't come back within two hours, you don't have to wait for me."

As he said that, Zhou Qi turned on the countdown for his waterproof electronic watch, which was 120 minutes.

The soldiers will also turn on the countdown.

When everything was ready, Zhou Qi no longer hesitated. He picked up the active sonar device and sat on the edge of the pipe leading to the underground abyss.

At this time, Zhou Qi suddenly asked the soldier in front of him: "Why do you think someone is willing to sacrifice his life to save you?"

The soldier was stunned: "Because of trust?"

Zhou Qi laughed and scolded: "It's so good to be young, I dare to believe anything."

Seeing that Zhou Qi was in a good mood, the soldier asked more: "Sir, don't you believe it?"

"Me?" Zhou Qi smiled: "I don't know if I believe it or not."

As he said that, he crawled into the water with his back and quickly disappeared.

Immediately afterwards, the soldiers also put the signal tower connected to the safety rope into the pipe. When the red and blue lights sank into the bottom of the pipe bit by bit, they were like the twinkling stars on the other side of the distance.

The underwater acoustic signal tower will be fixed in the underground river by a safety rope, lighting up Zhou Qi's way home.

...

At this moment, Luo Lan and others had set off again. Although Wang Run knew that there must be a problem with the incident just now, he could not determine where the problem was.

Time is tight, so he can't continue to get entangled with Luo Lan on the road.

"Do you think Zhou Qi will follow the plan?" Xu Man said: "He once said that entering the underground river would be very dangerous, right? If he couldn't find a way to retreat, he might die. He who loves money like his life has made so much money from Chief Qingzhen over the years, how could he bear to die in such a place?"

Luo Lan smiled: "If you think he only has money in his eyes, then you have misread him, otherwise why do you think he is willing to come to this Central Plains?"

"Do you believe him?" Xu Man said: "He is the most important part of this plan. If something happens to him..."

"Don't worry," Luo Lan shook her head: "I believe him."

While speaking, the convoy had arrived at the Artificial Intelligence Building in Barrier No. 61.

There was only a lonely black sign with the word "zero" on the top of the building, as if it was afraid that others would not know what artificial intelligence was called.

I saw a large number of Wang troops stationed around the building. Luo Lan muttered in a low voice: "Do you feel that this thing is like a soldier ants, a worker ants guarding the queen, it looks really numb."

"It's a bit like that," Xu Man nodded.

"It seems that the old man Wang Shengzhi is really gone. Generally, this is the only way to prevent mutiny," Luo Lan said with a lip slander, "But I haven't heard of anyone in the Wang family who can launch a mutiny? Isn't the power firmly in Wang Shengzhi's hands?"

"Maybe there is something inside that we don't know," Xu Man said.

Within the barrier No. 61, with the building as the center, almost every intersection within a radius of one kilometer was parked with black armored vehicles, and temporary machine gun positions were built.

When the convoy passed, all the Wang soldiers looked at them coldly, without any expression on their faces.

At the entrance of the building, there was already someone waiting there.

Wang Run got out of the car and said to Qing Lao San: "Mr. Qingzhen, this time you can only have you, Luo Lan and Xu Man, enter the building. Please wait on the outside."

Qing Laosan nodded slightly. This was something they had expected long ago. His current identity is Qingzhen, so naturally everything is based on what he means.

Wang Run continued: "And, before the three of you enter, you need to conduct a safety check and change your clothes to enter. Of course, it is not that you suspect that you are carrying weapons, but that you are weak and have low immunity. This examination is only given to avoid you carrying allergens and bacteria."

"Isn't it just that we are afraid that we will bring weapons in? They are so magnificent," Luo Lan murmured in a low voice.

Wang Run, who was beside him, heard this as if he hadn't heard it.

This time, Wang invited Qingzhen to the Central Plains, which ultimately came to be carried out with respect to each other.

Wang Shengzhi hopes that Qingzhen can take over the entire barrier alliance in the future, so he naturally has to give Qingzhen equal respect.

After entering Barrier No. 61, although Wang Run received an order to force them over, this was because Wang Shengzhi didn't have much time.

But during this period, even though Luo Lan and his convoy made a big trouble, Wang Run did not say a word of bad words, which was all explained by Wang Shengzhi.

So, even if you want to search, the security personnel in the building have to find a decent excuse.

Security personnel began to use various detection instruments to conduct strict inspections on Qing Laosan, Luo Lan and Xu Man to ensure that they did not bring any dangerous items into the ground.

At the same time, the three of them entered the arranged rooms and changed into dust-free suits.

Under this level of inspection, it is difficult to bring dangerous goods into the ground. However, Qingzhen had thought of this in his plan, so this plan requires Zhou Qi to cooperate.

Wang Run was waiting outside the door of the room. He looked at Luo Lan and the third brother of Qing, and Xu Man said, "Please leave the three of you to keep for storage. When you leave the underground, I will return it to you intact."

Luo Lan shrugged: "I brought a satellite phone and nothing else."

Wang Run said seriously: "The satellite phone must be handed over to me."

Luo Lan raised his eyebrows: "Why, is Wang treating guests like this? Our Qing family's No. 1 and No. 2 people have come to your Wang family's territory, and they even have to take away the satellite phone. Why are you guilty? Or are you not planning to negotiate with Qing family at all?"

But even when Luo Lan talked about this, Wang Run did not intend to give in at all: "All the satellite signals underground have been blocked. Boss Luo, even if you take this satellite phone, it will be of no use. I don't know what kind of security a satellite phone can give you, or there is another mystery in this satellite phone?"

Luo Lan smiled and said, "If you don't bring it, don't bring it."

As he said that, Luo Lan actually threw the satellite phone in his hand into Wang Run's arms and walked towards the elevator that went straight to the ground.

Wang Run behind him asked someone to use technology to detect the satellite phone, but found no abnormalities.

This made Wang Run a little confused. He obviously felt that Qingzhen, Luo Lan and others had another purpose in coming to Zhongyuan, but he couldn't figure out what the problem was.

In fact, there are two key points in Zhou Qi's actions. One is how to return after the task is completed, which requires an underwater acoustic system to act as a beacon.

The second point is even more critical, that is, how Zhou Qi found the underground server unit. He needed someone to enter the underground server unit to guide him on the navigation.

Equipment cannot be brought underground. The security procedures of the Artificial Intelligence Building are now rigorous and complex. However, Qingzhen never wanted to rely on equipment to do this. He relies on people.

Xu Man.

The abilities of extraordinary people basically have their own strengths and exist independently.

It is difficult for them to cooperate with each other unless they are as lucky as Ren Xiaosu, and they can bring Wang Yun, p5092, Xun Yeyu and the others together.

Now, the means used by Qingzhen to ensure that Zhou Qi and Xu Man cooperate with each other is scientific.

Before this, no one except Qingzhen knew that Xu Man had also become an extraordinary person.

As Qingzhen once said, if you want to cause severe damage to artificial intelligence, you must come up with something that doesn’t even count in artificial intelligence.

In the past two years, Qingzhen seemed to have thought about how to destroy the server unit under the barrier No. 61, and since then, this plan has been born.

During this period, Qingzhen has always maintained a mysterious whereabouts and rarely communicates with the outside world, so that artificial intelligence cannot obtain enough information from him.

Xu Man awakened in the subsequent war with Yang, but after Qing Zhen's explanation, he rarely showed his abilities in front of the outside world, and his abilities were more hidden: his control of sound.

This ability has been a bit useless in the past.

Because Xu Man can only emit ultrasound waves of about 20,300 Hz, it cannot directly cause damage to the human body, which is somewhat different from other extraordinary people.

Even Xun Yeyu, a white and fat man, has strong practical application capabilities in war.

What can we use for this 20,300 Hz ultrasonic wave? Generally speaking, the number of Hz in ultrasonic washing machines in civilian industries is several times that of this value.

However, another feature of ultrasound has been noticed by Qingzhen: ultrasound has extremely strong underwater propagation capabilities.

At this moment, Zhou Qi and Xu Man reached the most perfect way of collaboration because of sonar equipment.

Xu Man is another navigation beacon for Zhou Qi.

There has never been no useless ability in this world, it can only be seen whether you have found someone who can use it.

...

Underwater, Zhou Qi was moving forward quickly with his sonar device in his hand. He had not even swung his legs, but his speed was as fast as a fish.

The screen on the sonar device is like a bottom radar, and the green scanning optical axis keeps rotating.
To be continued...