The average height of the space of Vault 909 is 120 meters, and the area where the Cheng family's main residence is located has the highest space height, reaching more than 300 meters.

To excavate such a large underground space at a depth of hundreds of meters, it is certainly not feasible to rely solely on construction machinery to hollow out the rock formation, in addition to this, a large number of concrete and steel structures are required to reinforce, and this part of the expenditure is not less than excavating the rock formation, if not more.

At the time when the major consortia began to build shelters, the prices of cement, sand and steel skyrocketed almost all the way, and at the same time, housing prices around the world.

At that time, the local war between several countries had not yet evolved to the point of a world war or even dropping nuclear bombs on each other, and many people who did not smell the danger still thought that this was an opportunity to make a fortune.

However, not many people are investigating the reasons for this, everyone only pays attention to the numbers that keep jumping up, and clutches the pieces of paper that represent wealth in their hands.

No one expected that the war would come so quickly, and the day before, the government spokesmen of Huaxia and the United States were still spitting on the news programs over the issue of import and export tariffs, and the next day, the aircraft carrier fleet of the United States had sailed into the South China Sea.

From the full-scale outbreak of war to the launch of nuclear bombs, it was only a few short months.

Bonds, stocks, and certificates were all reduced to waste paper, and countless people went from billionaires to paupers overnight, and it was only then that the big conglomerates jumped out and began to sell people shelter beds, and they only accepted valuable things like gold, and paper money and checks were all rejected.

Those who put all their possessions on the market now have a problem even eating, let alone buying a valuable shelter bed – a situation that is naturally taken into account by the managers of the big conglomerates, who introduce a "loan system": they can provide a bed in the slum for those who cannot afford it, but after entering the shelter, they must work unconditionally for ten years to repay the loan.

At least 1 in 10 people are able to live in the shelter thanks to this loan system, and although they receive weekly relief supplies from the shelter's authorities, they can never save much money because all their labor is "free" to the shelter's ownership.

……

……

It's been almost four years since nuclear war, and it's been almost ten years since Vault 909 was built.

The metal frame fixed to the outside of the rock formation was already covered with rust, and every time both hands grasped it, a large amount of rust would be stained on the palms.

A team of less than 100 people, under the leadership of Cheng Yanqiu and Ghost Face, had unknowingly climbed directly above the Cheng family's main mansion with the help of the metal frame used to reinforce the dome.

It was only three hundred meters away from the Cheng family's main house, but no one noticed Cheng Yanqiu's approach.

In order to deal with the snipers, the light source of the entire underground space has been cut off, and only a few dozen searchlights are constantly sweeping around, but none of these searchlights are pointing at the dome directly above.

Cheng Yanqiu and dozens of other soldiers, each of whom carried a special backpack containing a set of low-altitude gliding devices, with the help of which they swept through the air like ghosts, and then landed unscathed on the roof of the main house of the Zhengxia Equation family.

"I thought these dozens of sets were going to be used to get through the mines, but I didn't expect them to be your last move." Ghostface looked at the dark-lit complex below and whispered.

"The defensive firepower of the Cheng family's main house is completely comparable to that of the Herrens Line, but its biggest weakness is that it does not have any air defense measures." Cheng Yanqiu squatted on top of an I-beam half a meter thick, and used a telescope with infrared thermal imaging to observe the situation below.

"Most of the people are concentrated on the side of the city walls and the fortress, and there are several patrols in the passage of the atrium, we have to avoid them, and the best place to land should be on the roof of the large warehouse in the direction of three o'clock, there are not many guards nearby, and it is only two hundred meters away from the center of the main house."

The center of the main mansion is where the head of the family lives and works, Cheng Yanqiu and the dozens of people want to take over the entire main mansion is obviously a fool's dream, but as long as Cheng Su can be controlled, or directly killed, then this war is over.

Although Cheng Su's personal guards are loyal to him, as long as Cheng Yanqiu gives them a chance to live, then no one will be willing to bury Cheng Su.

"Then jump there—" Ghostface glanced at his watch, "in four minutes, and that will begin." ”

"Well, in the last four minutes, everyone adjusts and checks their weapons and ammunition and gliding gear one last time. When the meeting landed, he immediately approached me. ”

"Understood."

Four minutes passed quickly, and when the seconds on the watch had just jumped to "00", the sound of violent gunfire and explosions suddenly occurred in the distance, and these deafening sounds continued to echo in the underground space, and even the metal frame where Cheng Yanqiu was living began to tremble slightly.

This was an agreed plan before setting off - although an attack from the dome could have the effect of catching you off guard, gliding through the air would inevitably make some noise, and once it was discovered by Cheng Su's men at this time, there would be no cover in mid-air that could provide shelter.

Therefore, when Cheng Yanqiu and the others almost arrived directly above the Cheng family's main house, the part of the soldiers who stayed in the barracks began to attack with various weapons, although attacking at this distance was simply a waste of ammunition, but it could provide enough cover for Cheng Yanqiu and them.

"Jump!"

Cheng Yanqiu let out a low snort, and dozens of pitch-black figures jumped down from the dome, their arms stretched outward as much as possible, and a pair of black wing membranes instantly spread, making the black shadow's falling speed immediately slow down.

Using their arms to control the angle of the wing membrane, dozens of black shadows quickly glided through the air, and when they were about to reach the target point, they retracted the wing membrane one after another and pulled out their parachutes.

It's less than 100 meters from the rooftop, but all of these soldiers are trained in ultra-low-altitude parachuting, and for them, an ultra-low-altitude parachute jump of 50 to 80 meters is as simple as drinking water.