After returning to the camp, Shadow found Shi Qian and asked. After learning that everything was normal around him and no enemy launched a sneak attack, he breathed a sigh of relief. He immediately introduced the Lei Jian to Shi Qian and asked about the Lei Jian's situation. He learned that he was hit on the head during the battle and fell down the hillside. Shadow saw a sunken crater on the Lei Jian's helmet. Fortunately, he was wearing bulletproof armor and a helmet, otherwise he would be dead.

Lei Jian also looked scared and very glad. Shadow comforted Lei Jian and asked Lei Jian to rest aside. He immediately reported the situation to Luo Zheng.

In the Duanpo Cave, Luo Zheng, who was deducing the next counterattack tactic with the think tank, secretly breathed a sigh of relief when he heard that there were survivors and told the Shadow to continue to squat on the front line and not to take the initiative to attack. After continuing to discuss with the think tank, he looked at Cao Xi and asked in a low voice: "How long will it take for you to find the underground river?"

"It's hard to say. I have noticed the surrounding terrain before. There are dry wasteland everywhere, and there are no plants, so it's hard to judge. It may take me three days, or two days at the fastest." Cao Xi said with some embarrassment.

It is indeed difficult to find an underground river on the barren and barren mountains. Three days is already almost done. Luo Zheng nodded in understanding and frowned and pondered. There is not much time left for everyone. Three days will definitely not work, not two days. Changes will occur over time. The think tank suddenly said: "I have an idea."

"What?" Luo Zheng asked in surprise, with a little more anticipation in his eyes.

"Don't worry, show me your drawing." The think tank said in a deep voice.

Luo Zheng was stunned and reacted. He took out his mobile phone and opened a drawing. The drawing was drawn by Xuelian based on satellite scanning. The satellite found that there were many heat sources underground, and it was drawn based on the location distribution of the heat source and combined with the appearance characteristics of the terrain. It can be said that this is an enemy's military deployment map. Although it is not necessarily accurate, it is roughly equivalent.

The think tank carefully identified the drawings, frowned, and fell into deep thought. Luo Zheng did not disturb him, but also thought about countermeasures. After a while, the think tank suddenly raised his eyebrows, and there was a little joy on his face. He looked at Luo Zheng and said, "Look at it, the entire underground base is distributed in the east and west, and the long passage you mentioned is also moving east and west, which should be this one." He said and pointed to a line on the screen.

"That's right, it should be." Luo Zheng replied in a low voice.

"The prison is next to the passage. You have been here. Are I right?" The think tank pointed to another location and continued, seeing Luo Zheng nodding affirmatively, she couldn't help but smile, relaxed and continued, "After confirming these locations, my speculation is basically valid."

"How do you say it?" Luo Zheng asked curiously.

"It's very simple, come on." The think tank scaled the entire map and revealed the overall overview and said: "The entire underground base is more than three kilometers long and more than one kilometer wide. Such a long underground fortification is only connected by a long passage, with more than two thousand people underground. How to solve domestic water? How to solve sewage discharge?"

"What do you mean is the underground fortifications built along the underground river?" Luo Zheng was stunned, suddenly reacted, and looked at the think tank in surprise and asked.

"That's right, only in this way can the people below avoid running around. They can use water if they dig a well to lead to the underground river. I was in prison for a while. The door of the prison was the only connection passage. I didn't see people transporting water at both ends. There was only one explanation, and people at both ends could use water." The think tank said seriously, his eyes shining with the luster of wisdom.

Luo Zheng was overjoyed and laughed. He was worthy of being the think tank of the Veterans Club. He was able to find problems through the details. At this time, the think tank continued: "The underground river trend is the same as the underground fortifications. The ground of the prison where I am is damp, which means that the underground river may be located under the prison. There is a hole for the prisoner's excrement and then flush it. At that time, we thought it was a pit that had been dug long ago. Now it seems that it should be an underground river."

"Wouldn't domestic water and sewage besides?" Tiede asked in surprise.

"No, they must have considered this issue when they were building it. They should have dug another branch next to the underground river as a sewage channel, and then diverted water into it to wash it. The distance is too far and the project is too big and inappropriate. There are two things we need to do. The first point is to make sure that it is upstream there, and the second point is to determine the specific location." The think tank said and looked at Cao Xi.

Cao Xi took the map and studied it carefully. While turning on his mobile phone, he called out a holographic topographic map to compare it. After a while, he showed a relaxed smile and said, "There is a river in front of the site, which is east-west. The upper reaches are in the west. Judging from the overall terrain around, the west is high, and the upper reaches of the underground river are more likely to be in the west. Perhaps the so-called underground river and the river on the surface are one, but because of the movement of the earth's crust or other reasons, there is an additional crack underground. When the river water pours into it, the crack becomes an underground river."

"What do you mean is that as long as you find the location where the river water is poured into, you can find the entrance to the underground river?" Luo Zheng asked in surprise.

"Yes, I'm sure of this. The terrain here is high, the mountains are steep, the land is barren, and the entire mountain range is severely weathered, not like there is a water source at all. Therefore, the possibility of underground cracks formed after the crust moves is high. The cracks are just connected to the river. When the river water is poured in, I guess the cracks are very large and very deep, and maybe they can be used." Cao Xi said confidently.

"Yes." Everyone had rich combat experience, their eyes lit up and they all laughed.

"The underground river is not conducive to people's passage. If it is a crack, it will be easy to deal with. We can penetrate directly into the enemy's interior through the crack and catch the enemy off guard." The think tank added in surprise, looking at Luo Zheng with his eyes full of fighting spirit, and his emotions also became high. He clenched his fists and looked like a big revenge and hopeful expression.

After being detained for more than three years, no one can let go of this hatred, not to mention that the other party is still a mortal enemy. The think tank is always thinking about taking revenge. The opportunity is right in front of him. The think tank is not calm, and Luo Zheng was also a little excited. If it is true as Cao Xi said, he would definitely be able to take the base in one fell swoop.

The closer he got to success, the calmer Luo Zheng was. Especially after the last black night, Luo Zheng realized that he had enough tactical attacks and insufficient defense. Faced with temptation, Luo Zheng did not act as impulsive as usual, but repeatedly pondered, thinking about what if he failed?

"What's wrong? Is there a problem?" The think tank asked curiously when he saw Luo Zheng silent.

"Are you sure it is a gap formed by the movement of the earth's crust, not an inaccessible underground river?" Tie Diao looked at Cao Xi worriedly and asked. This judgment is too important. If it is made, it will cause heavy losses.

Cao Xi corrected: "Underground rivers are basically formed by the movement of the earth's crust and can be passed through. The underground rivers in the plains are different from those in mountainous areas, and the underground rivers in mountainous areas are also different. They need to be treated in detail. I suggest going and take a look."
Chapter completed!