The Earth's environment, except for a limited number of places that have been treated, remains uninhabitable and full of radiation and harmful substances. In such an environment, it is difficult to imagine that there are people living underground, but Yuandou's mission today is to be under this surface.

According to relevant information, these people hidden underground are not from aliens, but have been living underground and living with humans for centuries. They have rarely had access to roads, but even so, there are still sporadic reports of the existence of the underworld. These news, which were strictly controlled by the countries that once lived on the earth, Liancheng proudly knew that when the earth was in danger and they were about to be subordinated, the underground world was finally exposed to the vision of some people. Of course, these people are people who have power, status, and are at the top of society. The underworld used to be just a human observing life on the surface, seemingly able to get along with each other, but when this state ended, their malice was completely exposed. In Liancheng's story, these people have their own beliefs, their own technology and civilization, and they are dismissive of surface humans and play with them.

From Liancheng's point of view, the dominated human beings are no longer considered human beings, so they have to rise up and get rid of the shackles. Every living being has the power to be free, and their domination infringes upon the power of human beings, and it is only for them to be crusaded.

Yuan Dou hovered in the air on a flying machine, looking at the information in front of him for a long time. There are many high-ranking generals and leaders of the Earth Army, who have become part of the underworld either voluntarily or under duress, all of whom share the same beliefs, the god who is in charge of the water of life, and who has many names, whether they are co-workers, or Poseidon, and so on. It appears in many myths, and is often represented in the form of a huge body covered with tentacles and eyes. The gods may just be legends, but Yuan Dou has personal experience to support them and will not think so. However, despite this, the god does not appear directly, and most of the time, it sleeps, like the earth that revolves around the sun, and remains in this sleeping posture for hundreds of millions of years.

In the information in front of Yuan Dou's eyes, there is also an unclear photo of the appearance of the underground person, which is a tall, blue-skinned, tentacled humanoid creature. The images are not clear, and it is not certain what they really look like, but it is still certain that they are not earthlings. Yuan Dou had never seen the images of these people, but Og was surprised to understand their situation, and he told Yuan Dou that this kind of legendary appearance of his dependents belonged to the bloodline of one of the Chaos Demon Gods. The fact that there are gods living beneath the surface of the earth is quite surprising to Mototo, and he is also worried about this mission.

There is no formed army on the surface of the earth to guard, and the only defense is the aura that was broken through by Yuan Dou, at this time, a large number of companions flew to a suspicious place to explore the passage into the underground world, and soon, most of the news was confirmed, and in the end, only the centaurs who went to the South Pole never replied. Although it is not 100% certain, most people believe that they have found the real way. So, Yuan Dou flew to the South Pole and followed the army into the cave where he had bottomed.

The cave is located within the Antarctic Circle, on top of an iceberg, covered in snow and ice. However, when the different layer of ice and snow was dug up, the hole was revealed. Facing the bottomless abyss, the vanguard rushed in without hesitation, but Yuan Dou belonged to the second batch of people who entered.

The size of the hole is neither large nor small, just enough for an aircraft to enter and exit. Yuan Dou rode Og's flying machine all the way down, through a curved tunnel, and came to a huge karst cave. Here, there are already people who have stopped again and gathered in front of a gate. It was a giant gate made of stone and more than ten meters high. Such a stone gate, Yuan Dou had seen it in Mercury, and he knew that through this door, he would enter a virtual world. However, the current situation is similar to that time, but it is a little different. When the stone door opened, the other side of the door was blocked by a white light curtain, making it impossible to see. But when he passed through the gate, the underground world was unobstructed in front of them, and it was an incomparably real world, so that Yuan Dou had no doubt about his authenticity.

Yuan Dou entered the gate and took the aircraft, and through the equipment on the aircraft, he quickly ruled out the possibility of the virtual world. So there may only be one left in front of Yuan Dou, and this is the real underground world.

The location where Yuan Dou appeared was near a huge city, which was still a karst cave, but it was extremely huge, and it felt like a continent. The ceiling is as high as it is invisible, but it emits a white light, which is the light emitted by bryophytes, and in such an environment, you can still feel the light even if you are underground.

Their arrival shattered the calm of the underworld, and the city reacted particularly quickly, immediately launching an attack on them. Weapons that fired blue lasers could be found everywhere in the city, and these weapons were sharper than anti-aircraft artillery, and their vanguard suffered many casualties from the first encounter. This counterattack may have been the lowest level of defense, and then, the tallest building in the city, an ancient castle, came out of which many enemies in black cloaks and armed with huge weapons. The weapon in their hands was like a walking stick, larger than the entire body, and when the blue gem at the tip of the staff lit up, it would unleash extremely sharp attacks. It was a current-like shot that could be destroyed with just the slightest touch of a mech or a flying machine. Under such an attack, the vanguard of humanity was overwhelmed, and soon retreated into the passage that had fallen into the air.

At this moment, a number of droplet-shaped flying machines rose up in the middle of the city, only a few cubic meters in size, and they rose vertically into the sky, and soon caught up with the strategically retreating vanguard. These aircraft may be individual combat units or unmanned machines, but they are extremely powerful and fast, using water as a weapon to unilaterally crush the human army.

Seeing that this situation was not good, Liancheng gave an order for a general attack to a person like Yuan Dou on standby through communication equipment. Yuan Dou immediately set off in a flying machine, and when he came to the sky above the city, he jumped down. Along with him are Lian Yan and Ye Xi, who will join the others in smashing the Yellow Dragon and capturing or annihilating the enemy's leader.