Seeing this, the wolf cub immediately rushed to the other side of the bulge, pulled out a spindle-like object with a tail from under the armpit of the armor, chiseled it the stone skin, and smashed it with a hard punch.

This spindle-looking thing is called a listener, which actually functions similarly to a stethoscope, that is, it can be used to listen to the sound of the ground, or it can be smashed on the enemy's battleship and listen to the sound in the battleship.

Of course, the latter is very dangerous, and since the invention of this thing, no commando has been brain-dead enough to do this.

Ye Fei's acoustic wave emitting device emits regular ultrasonic waves, the ultrasonic waves are dispersed layer by layer in the bulge, due to the difference in the sound resistance of the continuous and discontinuous medium, part of the sound waves appear partially reflected when the medium changes, when these reflected ultrasonic waves are received by the two people, the general structure of the drum can be drawn.

The detection found that there was a very large space under the bulge, but the thinnest part of the stone crust outside the bulge was also more than five meters thick.

"No wonder!" The wolf cub suddenly said, "Such a thick rock formation, even if you use explosives, you have to add a little more to blow it up, not to mention that I just smashed it twice...... Here's the spaceship, isn't it? ”

"I guess it's like there's a lot of space down there." Ye Fei said.

"What now? Blow it up? The wolf cub asked, pointing to the bulge.

"No, look for it first." Ye Fei refused, "If the three mountain people who escaped from the stone house were not blocked by the drone, they would definitely run here, there is a passage into the spaceship here, and the thing in the stone house was probably also taken out of the spaceship." ”

"Makes sense!" The wolf cub nodded his head, "But such a big ship." Where can I find the entrance? ”

The underground-sealed spaceship is more than four kilometers long and no less than a kilometer wide, and it is not easy to find a passage with a diameter of less than one meter in an area of four square kilometers.

"What else can I do, listen slowly." Ye Fei raised a finger and compared it to the depths of the cave.

The wolf cub sighed: "Accept your fate!" With that, he continued to go deeper for more than 100 meters in despair, smashing the listener into the rock under his feet.

Ye Fei stood still, activated the sound wave detection device again, and soon, the underground structure within a distance of 100 meters was roughly outlined, basically all rock formations.

The wolf cub couldn't help but shout, "Such a thick rock formation. Is it layer by layer? ”

"Possibly." Ye Fei said. "This place should be similar to the earth's karst caves, all the result of groundwater infiltration, as long as this ship has been here long enough, it is not surprising that a layer of limestone has been deposited on the ship."

It was rare for him to utter such knowledgeable words. It's a pity that the wolf cub just said yes and then disappeared. On the contrary, it made Commander Ye, who rarely showed Xiàn, feel empty in his heart.

The two of them probed the underground piece by piece. Several small caverns leading to underground ships were soon found, the largest and only one that allowed the battle armor to pass through guò, submerged under a small pool of water that was no more than a meter in diameter.

The two discussed a few words. The decision was made to dive into the waterhole to take a look, and the wolf cub drew his saber, jumped into the waterhole without giving up, and rushed down to the ground with his big head, and when he encountered a bumpy place, he repaired it with his saber a few times.

There are only two people in the cave, he and Ye Fei, dare to let Ye Fei jump down first, and after returning to the battleship, everyone must join forces to beat him, and the wolf cub can't take the initiative or not.

The wolf cubs that dived into the pool soon flew out.

"How?" Ye Fei asked with some anticipation.

"Not good." The wolf cub smiled bitterly: "There is nothing down there, this is a very deep pool." ”

"Damn, I thought it was an entrance." Ye Fei couldn't help but scold, "Let's try something else." ”

"That's a problem, the rest of the diameters are too small." The wolf cub scratched his head and said.

Ye Fei was full of confidence: "What's so difficult about that?" Wouldn't it be over just throwing a grenade and blowing it up? ”

Scissors hesitated: "Is this appropriate?" ”

"What's inappropriate?" Ye Fei asked rhetorically, "What are you worried about, this spaceship has been parked here for thousands of years, no matter how powerful the spaceship is, it will be finished long ago, even if there is a case, it will be over if the two of us escape immediately, hurry up." ”

"You're the head, listen to you." The wolf cub walked to another shaft-like hole with water droplets all over his body, picked up the grenade and threw it in.

There was a bang on the ground, and bright flames and rubble rushed into the cave, and the ash on the roof of the cave poured down, and the echo of the explosion reverberated back and forth in the cave for a while.

Without waiting for the smoke and dust from the explosion to dissipate, Ye Fei leaned over the cave and fired a beam of ultrasound into the hole.

"How's it going, boss?" The wolf cub asked expectantly.

"It's a little bit closer, throw another one." Ye Fei moved away from the top of the cave.

The wolf cub agreed, and threw another grenade into it.

The diameter of the burrow was sufficient, but the shattered rocks also covered the underside of the burrow.

The wolf cub didn't bother to jump down to clean up, so he simply planted a grenade in the rubble layer and blew it up again.

The explosion crumbled most of the debris out of the hole, but the debris that collapsed from the cave wall made the layer of rubble thicker.

The wolf cub and Ye Fei could only lower their heads and burrow into the ground to clear out the remaining rubble.

This time they finally found a real entrance, but the next two people were dumbfounded again.

Although the hatch is also round, there is no structure on the door that can be used to open the hatch, only a text symbol that I don't know what it means, and the circle around the hatch is wrapped into two concentric circles, one large and one small, which does not look like a hatch, but rather some mysterious artwork of unknown origin.

"Damn, is it possible to enter the door as if opening a treasure, and you have to guess the riddle first? Why don't you just put a Sphinx? The wolf cub couldn't help but swear directly.

"Come on, it's useless to talk about it, just keep doing it, blow it up!" Destruction Maniac Ye Fei said.

"Well, isn't that?" The wolf cub sneered, "If I go and get those mountain tribesmen, they must know how to get in." ”

"It's fine." Ye Fei nodded, "I'll wait for you here, go and come back quickly." ”

He estimated that this spaceship buried in the rock formation was the reason why the civilization inheritance of the mountain tribe had never been broken, and it was better not to destroy it, or not to destroy it.

And both of them only brought basic weapons, and the 5.5mm rifle did not have the ability to penetrate the hatch at all, and they had to go back to the assault ship to get a laser cutter to forcibly open this hatch that did not look heavy, but it was definitely not simple. (To be continued......)