Even though the old professor's face was quite ugly, Song Ziyu decided to stay after weighing it.

It's not just because of the coercion and temptation that the professor and this bullshit car pay attention to, but more importantly, Song Ziyu really doesn't know anything about the current situation, and he needs this place as a foothold.

After all, now that he knows very well that he is in the other world, and it is a world ruled by silicon-based life, he really needs someone to be a guide for him.

Of course!

Others saved their lives, and it was indeed necessary for them to thank the other party, so Song Ziyu reluctantly agreed, and temporarily lived in this base called Xiacheng, acting as a security guard for the base.

So with the personal support of the professor and the city lord of Xiacheng, Song Ziyu changed his appearance and became a member of the Xiacheng base.

Song Ziyu, who had a public identity, began to wander around this base called Xiacheng.

As the name suggests, the Lower City is actually a shelter space built underground.

There are about 6,000 people living in this shelter base, and most of them are yellow-skinned, unkempt, and look miserable.

In Song Ziyu's view, such an environment without childbirth and no security is actually only a matter of time before it dies.

During this time, Song Ziyu and Xiao Ai made friends.

This little girl who is only fifteen or sixteen years old is a character who does not hold grudges, and after some exchanges, Song Ziyu made Xiao Ai his little fan sister.

From Xiao Ai's mouth, Song Ziyu knew that the living environment of human beings in this plane was very harsh, and most of the human beings were hiding in a base like Xiacheng to survive, and life was very difficult.

After learning these facts, Song Ziyu couldn't help but sigh in his heart, when he crossed over to Longshan, he thought that the fate of human beings was tragic enough, but after arriving in Xiacheng, he really knew what it meant to be no worst but worse.

Grandma's!

Compared with the life of the people here, the people of Longshan live a prosperous life.

Nothing else, just saying the same thing, is enough to make people feel sick......

In the first few days of living in Xiacheng, Song Ziyu found that although this place was poor enough and lacking enough materials, every time it was time to eat, this place was always able to supply the "protein" food that Song Ziyu had eaten before.

Let's be honest!

This protein energy block doesn't taste very good, but it is still very worth eating from the perspective of energy supply.

This made Song Ziyu very curious.

What kind of family can eat this energy-rich food every day?

Song Ziyu felt extremely curious.

This place is so poor that it takes three people to wear a pair of pants, but it is magically self-sufficient in food...... It's really refreshed the three views.

However, Song Ziyu also found some strange details, for example, Ai Xin didn't like to eat this brown "protein energy block" very much, and would never eat this thing unless she had the necessary energy supplement.

"Why, you seem to hate this kind of thing?"

Song Ziyu asked while eating.

These days of recuperation, the dark injuries on his body have been so good that Song Ziyu has almost recovered eighty or ninety percent of his strength.

So Song Ziyu's appetite is very good.

"Seeing that you're eating so happily, I'm going to have to let you know what these things are made of."

Ai Xin said with a wicked smile on her face, and walked towards the depths of the Lower City Shelter with Song Ziyu on her face.

"Oh?"

Song Ziyu followed Xiao Ai to an inaccessible area of the lower city like a curious baby.

Here, Song Ziyu saw an incredible scene!

The area has been transformed into a pleasant environment, with a simulated sky and real meadows, surrounded by a large number of animals.

Such a scale of breeding made Song Ziyu feel incredible.

It also seems good to compare this place to the Garden of Eden of utopia.

"I didn't expect you guys to make such a big move underground! It's amazing. ”

Song Ziyu said in admiration, drooling as she spoke.

"Don't think about eating them, these animals are the key to the operation of the whole base."

Xiao Ai pointed to the poops pulled by the animals on the ground and said, "We still have to rely on them to defecate." ”

"Defecation? What is the use of this manure? Song Ziyu became curious.

"You'll find out right away."

Xiao Ai said with a wicked smile on his face, and took Song Ziyu through the underground farm, and then came to the next area.

Here, Song Ziyu saw a huge septic tank!

"It's ......"

Song Ziyu suddenly felt that the protein energy block in his hand was not fragrant.

Xiao Ai smiled evilly and said: "This is a separation tank, where the feces excreted by people and animals living in the lower city will be separated. ”

"Detached?" What do you mean?

Song Ziyu asked curiously.

Xiao Ai said: "First of all, you have to know the composition of feces!" Most of the manure is made up of water, which is very precious, and after entering the separation tank, it can be filtered, disinfected and purified, then purified, and finally turned into valuable fresh water. ”

"I'll go! You're not kidding, are you? Song Ziyu's eyes almost collapsed from their sockets.

"Do you think I'm a joker?" Xiao Ai put away the evil smile on his face and said seriously: "Seventy percent of the fresh water supply in the Xiacheng base is obtained by purifying feces and urine!" ”

"Then the water in your base can't be drunk."

Song Ziyu muttered.

It's fucking disgusting.

But Xiao Ai didn't care about Song Ziyu's ability to accept it at all, and continued to himself: "Of course, in addition to water, there are also a lot of solid parts in the feces. These solids include proteins, inorganics, fats, undigested dietary fiber, dehydrated digestive juice residues, cells and bacteria, and rare vitamins that humans rely on for survival. ”

Hearing this, Song Ziyu couldn't help but start retching.

"You're not going to tell me...... What Lao Tzu eats is pulled out by you? Song Ziyu wailed, feeling more painful than being slashed three times.

Unexpectedly, Xiao Ai's language attack has not ended there.

"You think that's it?" Xiao Ai said: "It's not all! ”

With that, Xiao Ai opened a conveyor pipe next to the septic separation tank, and then Song Ziyu saw a large number of cockroaches frantically swarming in the mixer.

This scene...... It is enough to make a dense patient with terror faint.

Song Ziyu successfully vomited.

"Don't feel disgusted, these cockroaches are protein-rich and taste good." Xiao Ai said.

"Dogs don't eat any of these things." Song Ziyu smiled bitterly.

Xiao Ai said: "When you are hungry enough, you will want to eat anything." ”

Some people died, but not completely......