As soon as they entered the alien base, Shu Xin and Lin Yucheng were surrounded by metal buildings with a sense of science and technology.

One shield, two worlds.

Inside the protective shield, there is an advanced extraterrestrial civilization; Outside the protective shield is a prehistoric civilization struggling to survive.

As a matter of fact, human civilization is regressing at a speed visible to the naked eye, returning to the primitive.

Under the pressure of survival, humans have to hunt mutated animals and plants every day to earn experience points and exchange Star Coins to buy various supplies needed for daily maintenance.

As for the development of other aspects, under the penetration of radiation, under the destruction of mutated animals and plants, and under the powerlessness of human beings, they have gradually disappeared in the long river of history.

"If I hadn't known that I grew up on Earth, I would have thought I'd traveled to another planet right now."

Every time he enters the alien base, Lin Yucheng will feel a little emotional.

"Boss, what do you think is the purpose of this alien coming to our earth?"

Shu Xin turned her head to look at Lin Yucheng, and after being silent for a while, she asked, "What resources do you think on Earth are worth coming from thousands of miles away from the vast universe?" ”

Lin Yucheng pondered for a while: "I've thought about this question before, but if you want to say that there are any resources on Earth that can attract aliens, I really haven't found out." ”

After the aliens came to Earth, they didn't actually do anything.

Except for the initial projection of a light source on the earth to digitize the earth, the aliens have been staying in the alien base since then, and they are rarely seen going out.

If they really want to be interested in a certain resource, they will definitely go to the field to test and study and excavate.

Lin Yucheng looked at Shu Xin and asked with a smile, "Boss, what do you think is the purpose of the aliens coming to Earth?" ”

Maybe it was because he came in too early, and there was no one in the base, Shu Xin glanced at these people whose complexions and spirits were obviously better than those in the dungeon, and said lightly: "Where does the alien invest the most, then what is his purpose." ”

"The most invested, the aliens didn't invest anything...... Lin Yucheng pondered, and suddenly, his eyes opened suddenly, and he looked at Shu Xin beside him with an indifferent face.

"Boss, you mean...... The purpose of the aliens is ...... We...... Mankind?! ”

Protective shields, alien bases, and alien malls are all investments from aliens, and the objects are earthlings.

Lin Yucheng's voice was a little loud, which made many people around look at them, Shu Xin was a little dissatisfied with this, and glared at Lin Yucheng: "Is this hard to guess?" Shocking you! ”

Lin Yucheng couldn't care about Shu Xin's emotions at the moment: "No...... Boss, what the hell are they trying to do? ”

The interstellar battlefield needs a lot of cannon fodder, and the earthlings reproduce fast enough, which is a very good choice.

Shu Xin quickly passed these words in her heart, and when she looked at Lin Yucheng, she said angrily: "You ask me, who do I ask?" ”

Seeing what Lin Yucheng wanted to say, Shu Xin stopped directly: "Okay, it's useless for you to think about this now, your strength is so low, you don't know if you can live well, thinking so much is like what problem you can solve." ”

If the problem is not solved, Lin Yucheng is itchy and wants to ask Shu Xin, but Shu Xin put on a posture of not entering, so that he is not interested in other things.

The alien base is divided into five regions, east, west, north, south, and center.

The Alien Mall is located in the central square.

After crossing a few streets, the alien mall appeared in Shu Xin and Lin Yucheng's sight.

In the central square, a silvery-white rectangular body of about one meter and glowing with metallic luster, centered on a launch column hundreds of meters high, is distributed in a circle from the outside to the inside.

Looking down from above, there are a total of 5 circles surrounded by silver-white cuboids.

From the outside to the inside, the first circle, which is the outermost circle, generally sells E-level equipment and materials, which is open to everyone.

In the second circle, D-level equipment and materials are sold, which are only open to soldiers of level 2 (inclusive) and above;

In the third circle, C-level equipment and materials are sold, which are only open to soldiers of level 3 (inclusive) and above;

In the fourth circle, B-level equipment and materials are sold, which are only open to soldiers of level 4 (inclusive) and above;

The fifth circle, which is the innermost circle, sells A-level equipment and materials (a small amount of S-level equipment), which is only open to fighters of level 5 and above.

After the digitization of the earth, the composition of the soil has been changed, and it is no longer suitable for growing food, and at the same time, the radiation levels in the bodies of animals and plants are seriously exceeded, and humans can no longer eat them directly.

As a result, until a solution can be found to remove radiation from plants and animals, human food sources will be deprived.

In this way, the alien mall has become an indispensable part of human life.

At this moment, there are already people lined up in front of each silver-white cuboid in the outermost circle, there are slightly fewer people in the second circle, even fewer people in the third circle, and there is no one in the fourth and fifth circles.

The further down the warrior level, the more difficult it is to move up, and the amount of experience required is too much.

Level 2 fighters need 100,000 experience points to upgrade to level 3; Level 3 fighters need millions of XP to upgrade to level 4, and that's not counting the XP required for daily life.

Take Shu Xin as an example, now she has 58,500 experience points, and after purchasing the preparation materials later, if the experience points are used up, she will have to earn another 100,000 experience points if she wants to be promoted to level 3 warriors.

Lin Yu wanted to queue up to buy E-level equipment and materials, but Shu Xin went directly to the second lap, and glanced at him before leaving, and he knew how to read his eyes, so he immediately followed.

The two walked towards the second circle, and everyone nearby raised their eyes to take a look.

In fact, when buying materials and equipment, you can roughly see a person's strength.

Like a level 3 fighter, it is absolutely impossible to appear in the first lap.

Seeing that the two stopped in the second lap, everyone withdrew their gaze.

There is a high probability that he is a level 2 warrior, which is not a strong person.

There were relatively few people in the second circle, and Shu Xin and Lin Yucheng didn't wait for a while, and it was their turn to buy.

If someone wants to buy goods, as long as they put their hand on the cuboid, a transparent light curtain will immediately pop up above the cuboid, and various equipment and materials will be displayed on the light curtain.

The former person is gone, the light curtain disappears, and the latter person continues.

When it was Shu Xin's turn, Shu Xin put her right hand on the cuboid, and in an instant, a blue transparent light curtain popped out.

"58,500 XP points detected, will all of them be converted into Star Coins?"

"Yes, No"

As soon as the light curtain appeared, these two lines emerged.

Shu Xin clicked 'Yes'.

Soon, the data in the Star Coin column became 5860. (5850+original remaining 10)

Immediately after, icons appeared on the light curtain.

Level 2 Nutrients: 5 Star Coins, which can maintain the energy consumption of a life form with a Level 2 physique for a day;

Level 2 energy liquid: 10 star coins, replenish water, remove a certain radiation value from the body;

Level 2 Trauma Spray: 100 Star Coins, which can quickly stop bleeding, scab over, and heal the wounds of life bodies with Level 2 physique;

N2 dose: 200 Star Coins, within level 2 physique, increase one physique point;

Level 2 Anti-Poison: 100 Star Coins, which can exempt Level 2 physique lifeforms from all poisonous gas and venom hazards, and is valid for 3 days;

D-level combat uniform: 500 Star Coins, which can withstand the upper limit of radiation of 1000;

D-Rank Combat Boots: 100 Star Coins;

D-Rank Gloves: 50 Star Coins;

D-level double blades: 500 star coins, which can kill level 2 mutant animals and plants, and a few level 3 mutant animals and plants (before 500 constitution points);

Night vision goggles: 50 stars (10 meters), 100 stars (50 meters).

......

There were many more after that, but Shu Xin didn't look at them, and she didn't need the others.

After some selection, when leaving the alien mall, the Shuxin equipment column displayed: 20 level 2 nutrients, 20 bottles of level 2 energy liquid, 5 bottles of level 2 trauma spray, 5 levels of level 2 anti-poison, D-level combat uniforms, D-level combat boots, D-level gloves, and D-level double knives.

In the star coin column, there is only 2410 left, which was directly converted into 24100 experience points by Shu Xin.