The next day at daybreak, everything in the shelter was running normally, with everyone performing their duties. However, everyone was moving more swiftly, adding a sense of urgency to the shelter.

Zhang Shi and Zhao Feng led a team of twenty people to their destination: two resource mines outside the shelter.

Zhang Shi carefully looked around along the way. Although he could find traces of creatures passing by, he did not find any zombies.

Unsure whether this situation was good or bad, Zhang Shi had no choice but to lead his team forward. After arranging the mining work, Zhang Shi and Zhao Feng chose a platform in the sulfur mine and set up the teleportation array. After instructing the soldiers on how to use it and the precautions, Zhao Feng stayed behind to supervise, while Zhang Shi himself walked to the plain outside the shelter, took out a high-quality resource generation card, and used it without hesitation.

In an instant, a small river more than ten meters wide appeared in front of him, surrounding the entire shelter. "Now I'm not afraid of another zombie horde, at least I have a buffer zone."

Zhang Shi found a spot relatively close to the opposite bank, and with a nimble leap, activated his Shadow Step to teleport to the other side. Pipi was already waiting for him on the shore, and upon seeing Zhang Shi return, she excitedly jumped onto his lap.

Inside the shelter, Ge Dalong and his men used wood and pig iron to create giant chevaux-de-frise. Ge Dalong tested its sturdiness with an iron sword and, satisfied, ordered his soldiers to mass-produce them. These things would be extremely useful during the next zombie horde.

Wu Qing moved the botanical garden to the side of the wall. Countless plants climbed up the golden stone wall, and various vines, thorns, and carnivorous plants stood on the top of the wall, completely surrounding the front of the shelter and making it look quite safe.

The engineers were still working diligently at the research center. Due to the shortage of weapons and equipment, Zhang Shi had added five more engineers. Now, the ten engineers were working intensively at the research center, refining steel, synthesizing gunpowder, or manufacturing weapons and equipment. In short, their work was of utmost importance, and Zhang Shi specifically instructed Xiao Mei to prepare some energy-restoring food, to be supplied to the engineers in unlimited quantities.

The support soldiers work with Wu Qing to prepare various medicines, and during mealtimes, they also assist Xiao Mei in preparing meals for everyone in the shelter, mainly handling logistical tasks.

The scouts were ordered to patrol the area around the shelter, keeping watch for zombies, especially in the woods behind the shelter. Last night, a large group of zombies gathered there, only escaping an attack because of the stream. Currently, although the temperature is slowly dropping, the river level has fallen to a dangerously low point, and he cannot use the resource generation card until the river completely dries up. Therefore, the back door has become a potential hazard, and Zhang Shi could only order the scouts to keep a close watch on it to prevent a zombie attack.

...

After Zhang Shi returned to the shelter, before he could even rest, Ge Dalong pulled him along and led a dozen assault soldiers to the main gate to dig a deep pit in the middle of the plain.

"Two lines of defense aren't enough to guarantee safety. Last night, we only encountered ordinary-level zombies, which already gave us a huge headache. I'm worried that the zombies might evolve over time. To prevent this from happening again, let's just be a little tired."

The shelter had been expanded several times and was quite large. Digging a deep pit around it was an enormous undertaking, with the total construction length exceeding one hundred meters. Even with high-quality tools, more than a dozen people still worked until noon to finish.

In the wilderness world, construction work is greatly simplified. By noon, the soldiers had copied more than twenty of the barricades that Ge Dalong built in the morning.

Ge Dalong put the barricades into his backpack and then arranged them in a certain way along the edge of the deep pit, forming the third line of defense for the shelter.

After a hard day's work, Zhang Shi worried that another horde of zombies would arrive that night, so he specially arranged for some sheep to be slaughtered to reward the soldiers. Even the mining team in the mines got to eat freshly roasted whole lamb through a transaction with Zhao Feng.

The soldiers already respected and were loyal to Zhang Shi, and after last night's fierce battle, they felt an even stronger sense of belonging to the sanctuary. Zhang Shi then treated them to lavish meals, which moved these soldiers, who hadn't lost touch with their past experiences, to tears of gratitude. They all expressed their willingness to die for Zhang Shi.

It's a joke. The time and money cost of a single soldier is considerable. How could Zhang Shi bear to let them suffer losses? Before the antidote becomes available in large quantities, Zhang Shi will not allow any soldier to engage in close combat with the horde of zombies.

In the afternoon, Zhang Shi received another piece of good news. The professional skills upgrades for engineering corps differed from the regular upgrade process. Perhaps due to several days of intense work, Gong Yi had actually been upgraded, his title changing from engineering corps to craftsman.

Zhang Shi checked his attributes and found that apart from the grade becoming high, the other attributes remained unchanged. He then called Gong Yi aside and questioned him personally.

"Reporting to the lord, after the upgrade, I feel that my construction speed has been significantly improved, many memories have flooded into my mind, and I have learned the crafting techniques for several items."

After listening, Zhang Shi became interested and asked Gong Yi to narrate the story in turn.

A moment later, Zhang Shi's ears were drawn to the word "cannon," and his eyes lit up. After confirming that the cannon Gong Yi had mentioned was the same artillery that fired shells from his memory, Zhang Shi's voice trembled with excitement.

"Go, go make it now, and call me as soon as it's done!"

Gong Yi noticed the lord's emotional fluctuations and immediately jogged back to the research center to get back to work on the cannon's production.

Last night's defensive battle relied on primitive methods like catapults for launching explosives, resulting in short range and low frequency of attacks. If Gong Yi's cannons were truly effective, they would be enough to rewrite the battlefield situation. A single volley would obliterate even the largest number of zombies, and the soldiers wouldn't have had to fight all night without completely clearing out the horde.

As sunset approached, Zhao Feng led his mining team back home laden with their spoils, their backpacks overflowing with sulfur and saltpeter. Zhang Shi delivered all these mineral resources to the research center. Just then, Gong Yi finished building the cannon, so Zhang Shi led everyone to the wall to test it.

Zhang Shi first glanced at the cannon's attributes.

[Iron Cannon (Green): A primitive firearm capable of firing various types of ammunition. It boasts a long range, high power, and is easy to carry. Different shells can produce different effects, making it a nightmare for infantry.]

Turning our attention back to the main body of the cannon, its main structure is a barrel, with a carriage and pulleys attached below for easy transport. The barrel is made entirely of refined iron. After ammunition is loaded into the barrel, it can be fired via a mechanism at the stern. Inside the mechanism, a flint ignites the gunpowder in the chamber, thus igniting the ammunition.

Gong Yi took out an explosive shell specially made for the cannon, loaded it into the cannon barrel, and then signaled to Zhang Shi that he could fire.

Zhang Shi slowly turned the cannon's breechblock to adjust the angle, aiming at the small river a few hundred meters away.

"Bang!"

As Zhang Shi pressed the trigger, the cannonball was successfully launched. Moments later, the explosive shell landed in the middle of the river, creating huge waves. Many fish and shrimp in the river were blasted into powder, and the river immediately became much more turbid.