The raw materials were readily available in the warehouse. The power units came with variable adapters, capable of drawing power from a generator or plugging into fusion cells with standard interfaces.
Just like the black box Chu Guang had retrieved from the Administrator's Office in Vault 117, the black boxes here came with built-in batteries, showing remaining charges of 98% and 99%, respectively.
Helium-3 was a stable isotope with an extraordinarily long half-life, meaning loss from natural decay was practically negligible under normal usage. As long as improper operation or other accidents didn't physically damage the cell itself, it would retain power far longer than conventional chemical batteries.
Via his VM, Chu Guang instructed Guo Niu to deliver all the required materials and summoned Shelter 404's chief prospector and scientific expedition leader, Dr. Yin Fang.
The moment Yin Fang stepped through the door, his eyes nearly popped out of his head.
"Black boxes?! Two of them?! Where on earth did you get these?"
S-tier relics!
Two of them at once!
Just the day before yesterday, Chu Guang had brought back one black box, and now, not even three days later, he had secured two more.
In the five or six years since graduating and becoming a prospector excavating pre-war ruins for the Academy, Yin Fang had never witnessed anything so absurd!
Seeing the man's flabbergasted expression, Chu Guang rolled his eyes and tossed the newly retrieved instruction manual into his hands.
"Found them lying around. Take a look and see if you know how to work them."
Yin Fang gave an embarrassed chuckle. "A fool could use these, okay? ...By the way, have you checked the reactor's fuel? How much is left?"
"Surprisingly quite a bit. Around forty percent."
Chu Guang wasn't entirely sure what forty percent entailed. If it were a smartphone, his charging anxiety would have kicked in by now, but for a controlled fusion reactor, even one percent of its output was said to last a very long time.
He didn't know how much power clone synthesis consumed.
Regardless, with the reactor finally secured in his hands, the weight on Chu Guang's mind had lifted.
Hearing Chu Guang's reply, Yin Fang visibly breathed a sigh of relief as well.
"Forty percent? That's great... No need to worry for quite a while!"
With no lingering concerns, Yin Fang began operating the two black boxes.
He loaded the materials sequentially into the drawer-like feeder chute according to the manual before sliding it shut. Loading them out of order would also work, but following the sequence was slightly faster.
An indicator light turned on, confirming the materials met specifications.
Next, he flipped the power switch and pressed the start button.
The entire process was complete—effortless.
It was so simple it felt almost like a religious ritual.
Watching the numbers ticking down on the screen, Chu Guang rubbed his chin.
"Time remaining: 59 min 27 sec... It takes that long?"
The smaller black box beside it, which produced VMs, was considerably faster, requiring only ten minutes to manufacture a unit.
Assuming an uninterrupted supply of raw materials, it could theoretically turn out 144 VMs in a single day.
These things were priceless.
Equipped with a processor, display screen, and lidar mapping capabilities, a VM was not just a vital signs monitor; it could also be repurposed into other devices.
For instance, a robot capable of lidar mapping and autonomous pathfinding.
Or a basic computer, among other things.
Combined with the neural link devices manufactured by the black box Dr. Principle left behind in Vault 117, as long as they had enough materials, players' modification ratings might jump by ten percentage points!
A true golden age was dawning for Intelligence-type players!
It was extraordinarily useful.
"I've heard that black boxes operate by first pulverizing the materials into powder," Yin Fang said, "and then, following a preset synthesis pathway, printing each component layer by layer in 3D space to construct the product as a whole... Compared to an assembly line, it naturally takes longer."
Chu Guang asked, "Kind of like manufacturing the wheels and the engine at the same time?"
"You could put it that way!" Yin Fang affirmed.
Chu Guang nodded thoughtfully in understanding.
It was like a 3D printer.
Yet its capabilities went far beyond ordinary 3D printing. Not only could it print the geometry of components, but it could also replicate the material's physical properties as well as the microscopic and macroscopic structures, assembling everything automatically during the printing process.
This went far beyond the concept of "printing."
It was closer to atomic reconstruction at the picometer scale!
Standing off to the side, Xia Yan scratched the back of her head, completely unable to chime in on such a tedious topic.
She knew how to fix machinery with a wrench, or machine parts on a simple workbench—after all, the slums of Boulder City sat right next to the industrial zone. People there had only two paths in life: work until they dropped on an assembly line or in a workshop, or pick up a factory-made weapon and become a mercenary, trading their lives for coin.
And she happened to have walked both paths.
Thinking it over, Xia Yan felt staying completely silent would make her seem useless, so after holding back for a while, she managed to pipe up:
"Sounds pretty handy, this machine... Can we crack it open and take a look inside?"
Chu Guang didn't react, but Yin Fang jumped as though his tail had been stepped on and blurted out in panic:
"Don't you dare!"
Xia Yan scratched her head. "Why? Shouldn't something like this make great research material?"
Hearing her layman's remark, Yin Fang shook his head.
"It's basic common sense: the more technology-dense a product is, the harder it is to reverse-engineer. Finding a grain of gold in a pile of sand only requires sifting it out. But if you're asked to stand on a sand dune and categorize every single grain of sand, it's an impossible task... unless you already possess far more advanced tools and methods.
"Black boxes from Project Ark, both in production methodology and underlying technology, represent the pinnacle of the People's Federation's manufacturing. They demand nothing of the operator's education—or even intellect—and have negligible requirements for material grade. Even a monkey in a zoo could operate one.
"These wishing machines are the technological crystallization of pre-war civilization. Unless a civilization surpasses us by leaps and bounds in both manufacturing and fundamental science, no one could ever extract what they need by taking apart such an intricate apparatus."
Xia Yan mumbled, "I was just asking offhand, not saying I was actually going to dismantle it... But if this thing is so fussy, how do you fix it when it breaks?"
"You don't. Once it breaks, it's done for," Yin Fang replied, shaking his head. "At the Academy, a broken black box usually ends up in a museum. Maybe hundreds of years from now someone will decipher it... but for now, it's out of the question. We'd rather study the products turned out by the black boxes; at least that's far less difficult."
Yin Fang's answer cleared up part of Chu Guang's questions.
It seemed even the Academy lacked the capability to reverse-engineer the technology within the black boxes, settling for analyzing the items they produced.
Glancing one last time at the timer on the screen, Chu Guang spoke up.
"Looks like we still have some time before the mystery reveals itself... Let's go check out the buffer room next door."
Yin Fang was taken aback. "A buffer room? Isn't this Floor B3?"
Chu Guang nodded. "That's right. Shelter 404 has more than one door. I'm inclined to believe the door on Floor B3 is the actual main entrance."
Spatial layout-wise, the Floor B3 blast door was noticeably wider than the one on Floor B1, and it connected directly to the warehouse and planting area.
What did that imply?
It implied that the shelter had most likely been constructed starting from Floor B3, expanding upward and downward simultaneously!
Of course, this was only Chu Guang's conjecture. If they found an even grander exit on the lower floors, he would take it back.
Every time Chu Guang thought he fully understood this shelter and the first-generation manager's plan, the vault beneath his feet would always surprise him.
Chu Guang even suspected that whoever designed this shelter had probably been a game developer.
...
Everything beyond the Floor B3 gate was an unknown; no one could predict what they might encounter.
Optimistically, it might be an Easter egg left behind by the first-generation manager.
Pessimistically, it could be a nest of mutant rats or roaches.
To be safe, Chu Guang brought his power armor down from the prep room on Floor B1. Along with his Nitrogen Power Hammer and Gauss rifle, he also grabbed two Scythe assault rifles, a bulletproof vest, and a backpack packed full of 7mm ammunition.
The body armor was for Boss Xia.
Back in the Floor B3 prep room, Chu Guang tossed a Scythe assault rifle and a police vest over to Xia Yan.
"I assume I don't need to teach you how to use these."
Slipping the vest over her torso, Xia Yan tied her long red hair into a ponytail and picked up the rifle leaning against the wall.
"Are you kidding? I was a..."
"A mercenary who served as an extra drumstick for a Crawler's boxed lunch?"
Seeing Xia Yan glaring murderously at him, Chu Guang hastily clicked his visor shut, coughed, and took the lead.
"Stay close."
Xiao Qi rolled along on its wheels with a whir, trailing right behind Chu Guang.
Seeing that he was the only one without a weapon, Yin Fang hurried after them and asked, "What about me? Give me a weapon too! If anything happens, I can fight!"
Chu Guang thought for a second, unhooked the Silver Snake revolver from his power armor, and tossed it to him.
"Remember to return it."
"Only six rounds?!"
"If the need arises, I'll give you more."
Pulling down the lever on the control console, Chu Guang pressed the red button.
The alarm inside the prep room chimed three times.
Lock bolts as thick as thighs retracted one after another, and the cog-shaped alloy blast door rolled slowly to the side, revealing a pitch-black tunnel.
A cold, dry draft rushed over them.
Chu Guang switched on his shoulder-mounted searchlight and advanced with his Scythe assault rifle raised.
Their boots crunched against the ground. The dust here was thick; no one had set foot inside for a very long time.
The tunnel was pitch-dark—so dark one couldn't even see their own hand in front of their face.
Fortunately, the power armor was equipped with lighting, and the other two were carrying flashlights.
By the beam from his shoulder light, Chu Guang could see steel rails laid across the ground, along with a few construction tools scattered around.
"This tunnel isn't on the map," Yin Fang said after checking his VM. "Directly south of us lies Qingquan City's Subway Line 12, about four kilometers away in a straight line! Directly north aligns with the outbound elevated highway, heading out of Qingquan City."
Line 12 ran north-south through Qingquan City, and Huayuan Street Subway Station was one of the stops along it.
Chu Guang tapped the side of his helmet with his index finger, bringing up the map on his visor.
An amber-tinted HUD projected across his tactical eyepiece.
The closest subway station was near Bet Street, roughly 800 meters away.
Chu Guang had been there before, though he hadn't ventured inside; he had only glanced in from outside and seen it completely overrun by gnawers.
Most likely, other nasty creatures lurked within as well.
"What about heading north?"
Yin Fang blinked, dragging the map. "North... We're already on the northernmost fringe of Qingquan City. Further north leads outside the city limits, and there are no subway lines marked on the map."
The tunnel ran north to south, with the shelter's exit situated along its side. Stepping past the blast door, they could head either north or south.
"Let's check the north side first."
With that, Chu Guang took the lead, guiding the team northward.
After advancing roughly 800 meters, the tunnel came to an abrupt halt, blocked by an alloy wall.
"Looks like a dead end," Xia Yan said, shining her flashlight forward before turning to Chu Guang. "Should we turn back?"
Chu Guang studied the wall for a moment, then walked over to the side, where he discovered what looked like an electrical panel.
Flipping open the cover, he saw a lever handle and a circular port.
Curiously enough, the circular port was a perfect match for a small cold fusion cell.
His interest piqued, Chu Guang pulled a cold fusion cell with 11% charge from his pocket and slotted it into the port.
Then, he pulled down the adjacent handle.
A faint hum of electric current rose, accompanied by a grating screech of friction, followed immediately by a subtle tremor beneath their feet.
It felt like an earthquake!
"What's happening?!"
Panicking slightly, Yin Fang glanced around and stepped back twice.
Xia Yan remained relatively calm. Her eyes darted alertly toward the ceiling and then back forward, widening slightly.
"It's the wall! It's sinking!"
Xiao Qi rolled up beside Chu Guang's calf, piping up anxiously, "Master, it's dangerous here! Why don't we pull back first?"
"Don't panic. Wait a second!"
Chu Guang's gaze was locked onto the wall ahead.
It descended slowly, and after an earth-shaking shudder, the tunnel behind it was finally revealed.
Only then did everyone realize the wall was over a hundred meters wide!
It was like an entire section of the tunnel had been lifted!
"Incredible..." Yin Fang took two steps forward, awe written across his face.
Such a thick concrete structure—it had to weigh at least tens of thousands of tons!
Factoring in the internal mechanical systems and load-bearing structures below, it was practically equivalent to burying an aircraft carrier underground!
The comparison might not have been entirely precise, but the scale was comparable.
Surprise was mirrored on Chu Guang's face.
The mechanism itself wasn't complicated.
What was truly astonishing was that more than two hundred years later, it could still be activated and operate without a hitch!
While the two were still dazed, raspy roars and frantic scuffling footsteps echoed from further down the tunnel.
Hearing that sound, Xia Yan started, instantly snapping up her assault rifle and flicking off the safety with a swift flick of her index finger.
"Gnawers! Ahead of us!"
Before her voice had even faded, she had already squeezed the trigger, taking down the two closest gnawers with three-round bursts.
"Looks like the noise drew a bunch of them."
Engaging the assisted-targeting mode on his tactical visor, Chu Guang raised his Scythe assault rifle and fired a burst. The nearest gnawers' heads exploded instantly, and they dropped dead on the spot!
Just then, an ominous premonition struck.
"Damn it, a Crawler—" Panic flashed across Xia Yan's face as terrifying memories resurfaced.
Yet in the very next instant, that Crawler's head was blasted into pieces.
"Don't panic. I've got you."
Slinging the Gauss rifle onto his back, Chu Guang took hold of the Scythe assault rifle again, deftly toggling back to full-auto and cutting down several rushing gnawers.
Severed limbs and mutilated bodies littered the ground.
A rancid stench of rot permeated the passageway.
Sheltering behind them, Yin Fang exhaled in relief, lowering his raised barrel.
Looking at the dead gnawers on the ground and the black splotches and slime mold covering the distant walls, his Adam's apple bobbed with difficulty.
"I have a feeling... there are a ton of mutants up ahead!"
"You don't need a feeling for that; anyone with eyes can see it," Chu Guang paused, then added, "We'll leave the area ahead for the 'players' to explore."
With that, Chu Guang lowered his rifle, tapped the side of his helmet twice to bring up the visual interface, and began adeptly composing quests.
[Quest: Clear the Floor B3 Exit]
[Type: Hunting, Exploration, Assault]
[Description: The tunnel outside the Floor B3 entrance has been overrun by slime-mold-type mutants. We must take it back from those beasts!]
[Target Audience: Hunters, Scavengers, Soldiers, and players above LV5]
[Rewards:
For every gnawer killed: 1 silver coin, 2 contribution points.
For every Detonator killed: 1 silver coin, 1 contribution point.
For every Crawler killed: 20 silver coins, 20 contribution points.
For every Tyrant killed...
...
]
——
[Quest: Explore the Floor B3 Tunnel]
——
[Quest: Investigate the Slime Mold Contamination Source in the Floor B3 Tunnel]
...
A total of five quests were posted to the quest channel, freely claimable by players who met the criteria.
This should make for a fine leveling spot.
Even ten thousand gnawers would only cost ten thousand silver coins.
Even tacking on five hundred Crawlers would only be another ten thousand silver coins.
This way, players gained experience, honed their proficiencies in shooting, archery, throwing, and hand-to-hand combat, and earned money to boot.
Simply flawless!
If he could secure an active substance extractor, he could deploy one here as well.
The extraction efficiency for gnawers was mediocre—roughly ten bodies to yield one unit of active substance. But even mosquito legs had meat; tiny gains would compound into a tidy sum, which beat leaving mutant carcasses to rot and reek in the tunnel as breeding grounds for pathogens.
And all he had to pay were some numeric values that could be tweaked whenever he pleased.
At this thought, the corners of Chu Guang's mouth curled into a faint smile.
Since all the perks went to the players, let's call this a double win for the players!
Glancing at Chu Guang with admiration, Yin Fang couldn't help marveling, "Those 'players' of yours are ridiculously useful."
They were the very epitome of enduring hardship and toil.
He had never seen vault residents who worked this hard!
Chu Guang quipped, "Looks like you're gradually grasping the true essence of this game."
Hearing another incomprehensible word, Yin Fang blinked. "Youxi?"
"Contextually speaking, it means harvesting chives."
Yin Fang: "...?"
Chapter 191