The sound of Xu Xin's watch was played externally, so Ma Hongwei and Zeng Tao could hear it.

Both of them were surprised and turned to look at Xu Xin's watch.

"Underground? Drill a hole underground and get in?" Zeng Tao exclaimed.

"Underground..." Ma Hongwei immediately frowned.

It's fine in heaven and on earth, but underground...

His ability doesn't seem to be able to handle this situation.

Xu Xinze thought a lot in an instant.

Drilled into the ground... This possibility should have been considered!

Although there is a safe zone around the tree house, and the roots will protect the surrounding land from infringement, but...

That might only be useful for those low-level wild mutated animals and plants!

At this time, the World Tree has not really grown, and the root system is at its most vulnerable.

"Why do you all think so?" Zeng Tao curled her lips.

Simply doing some damage will not kill the tree house. If you want to destroy the tree house from the ground, you need to cut it directly.

There are also three pangolins that dig extremely fast.

Ten meters, that’s the height of a three-story building.

"It's possible."

Zhao Xiaochuan: "Drilling holes underground... I thought it would be the safest to have the World Tree and the roots of the tree house guarding the ground..."

"That is to say...last night?"

They are all too familiar with what will happen to a treehouse that loses its core.

Indeed not.

"Now that we know it, how can we solve it?" Wang Lei pointed to the ground, "We don't seem to have any way to deal with the mutated creatures that burrow underground, right?"

If you can reach the position of seven or eight hundred meters, you will definitely be able to continue deeper and directly enter the center of Crystal City and reach the location of the World Tree.

Qi Xuefei: "Okay."

Qin Fu once again described the situation in the cave in detail.

Concubine Ai should have been promoted to an intermediate mutant creature now!

Yes.

These passages may be just for the other party to test whether they can dig a hole underground to enter the Crystal City and get close to the World Tree."

"What if we come from farther away?" Qi Xuefei asked.

"No, there is only a long hole. This one is even longer. There is..."

Qin Fu was out of breath and obviously running: "Just to the east of Crystal City, I found a cave dug underground. The depth is about five meters underground. This cave is about five or six hundred meters deep into Crystal City.

!”

"I also think so."

"I won't go." Ma Hongwei waved his hand, "I can only be responsible for the guys digging holes above the ground, in the air, and underground... I can't handle it, so why not do more research."

"What a great idea!"

Treehouse Core…

"Dig ditches." At this time, Qi Xuefei proposed a plan, "Dig a deep and wide enough ditch around the World Tree. In this case, it may be able to stop the pace of underground digging. If they dig out and enter

We can also attack in the ditch. The treehouse heavy crossbow can also come in handy."

"If it were me, I would do this. When a large number of mutated creatures appear together, some of the mutated creatures will burrow into the ground and will not be conspicuous.

At this time, Ma Hongwei sat in front of his test bench, put down the drawing in his hand and said, "If there are only three caves, is it just a test?"

Except for Wen Guixin, who was a little far away, and the person involved, Qin Fu, everyone else arrived.

"Why?" Wang Lei was a little puzzled. "The root system of the World Tree is so developed. It won't be of any use if they destroy just a few roots. It still needs to be severely damaged. It's not as good as the ground. You still have to dig soil underneath."

"Are there only caves?" Xu Xin asked immediately, "Are there no wild beasts or mutant creatures?"

Xu Xin looked at the World Tree again.

"Okay." Qin Fu nodded, "That's it..."

Xu Xin's words made everyone present slightly change their expressions.

Seeing Xu Xin looking at her, she nodded slightly, indicating that she had fully recovered.

On the other side of the voice, Qin Fu spoke again.

"Are they going back to call for the army?" Zhao Xiaochuan said worriedly, "Isn't that coming soon? We must think of a way as soon as possible!"

"First of all, there is the Crystal City above. It is difficult for them to get in." Ji Chaoyang patted the World Tree, "Secondly, this World Tree is also a treehouse. It should... also have a treehouse core."

"No." Xu Xin expressed her thoughts, "Maybe, it won't be so fast."

And this world tree seems to need a few more days to grow.

"Let's go."

Everyone frowned, thinking about how they would respond if Xu Xin's conjecture came true.

Xu Xin glanced at the World Tree again.

"Yes, the underground passages they dug are probably not connected, and it may not be easy to infect a large area." Ji Chaoyang also said, "Moreover, we must also beware of the very powerful creatures that may appear underground.

Wen Guixin cannot be infected in a short period of time."

He walked directly towards the place where the crowd gathered under the World Tree.

The figure is more straight and the skin is supple and supple.

As for why he returned at a distance of seven to eight hundred meters, Xu Xin believed that the closer he got to the body of the World Tree, the more developed and dense the root system of the World Tree would be, and the difficulty of excavation would also increase exponentially.

Everyone, including Xu Xin herself, felt a chill.

"When I excavated, there were no more." Qin Fu responded, "There is only one cave left... less than one meter in diameter. It is very narrow. If people want to enter, they will probably have to crawl. Digging the hole

The creature should not be too big."

"So deep..."

"We have prepared many ways to deal with enemies on the ground and in the air. We have the Treehouse Heavy Crossbow, which has good anti-air capabilities. Coupled with Sister Gui Xin's ability, the beasts will not be a threat."

"Qin Fu, please explain clearly what you discovered."

"Where is the location?" Xu Xin asked again.

Xu Xin has map ability, and large red dots appear around him. How could he not notice it?

"Another underground cave was discovered?" Xu Xin also stared, "Where are the mutated creatures? Are there any mutated creatures that are digging?"

"No." Xu Xin directly denied her statement, "Seven to eight hundred meters is already very deep. If it would be affected, it should have been affected long ago."

"That makes sense!"

"We need more diggers." Xu Xin squinted his eyes and looked out the window, "So, they are going back to invite a large force."

Let that infected guy infect the entire underground legion!

Let them all die underground!

"What a great idea!" Wang Lei clapped his hands, then laughed and said, "Haha, with Sister Guixin here, it will be much easier to deal with the beasts!"

Pangolin concubine and those two little guys?

The root system of the World Tree has a very wide range and can even affect the entire area 188. They cannot destroy it at all.

Maybe we can just dig out the core of the treehouse of the World Tree!

Looking at the World Tree again, it is still growing, but the speed is not as fast as before, and it can no longer be seen if you don't look carefully.

but……

"No, this morning!" Qin Fu asserted, "This cave was definitely newly dug this morning!"

"It's just a few meters outside Crystal City, but the entrance to the cave is flat and has been filled in. There's no trace at all."

No...probably not.

Xu Xin also wanted to leave immediately.

All the trees near Crystal City have disappeared. If it hadn't been for the tree planting this time, Qin Fu might not have noticed it at all.

After all, Lou Fei'er is also in the group and can also see Xu Xin's news.

"Drilling holes underground..." Wang Lei stepped on the ground, "This alien invader really uses all kinds of despicable methods. Do they want to steal homes directly from the ground?"

Is this world tree a bit... too thick?

Xu Xin and Zeng Tao got off the tree house and came to the edge of the World Tree.
To be continued...