At the same time.

Bai Zhen and Wang Ning sat in the living room reviewing materials. The paper documents Zhao Bowen brought back could fill one suitcase, and the electronic files could fill another suitcase. This afternoon, when Zhao Bowen stacked the colorful folders one by one until they exceeded the height of everyone present, Old Bai and Old Wang, thought this guy had just ransacked the printing shop downstairs. Then Zhao Bowen turned around and pulled solid-state drives from his suitcase, stacking them one by one until they too exceeded everyone’s height—looks like this guy had ransacked the electronics mall too. Old Zhao patted the folders and hard drives on the tea table, telling everyone this was all the work they had done over the past half month.

Both men found it hard to imagine that Zhao Bowen had completed such an enormous amount of work in just half a month. They looked through while clicking their tongues in amazement.

“Nanjing City high-altitude ionosphere F2 layer… balloon-suspended radar reflection experiment…”

“September to December China East Region electromagnetic signal full-spectrum wide-area monitoring records.”

“September to December sunspot activity and Earth magnetic field variation monitoring records.”

“Cosmic microwave background radiation spectrum… what’s this? CERN? European Organization for Nuclear Research?” Bai Zhen furrowed his brow, holding a stack of papers all in English, he only understood one-word ‘Nuclear’, “Nuclear weapons? Impressive, you guys even got nuclear weapons?”

“CERN, European Organization for Nuclear Research,” the River-Crossing Rat sitting opposite Bai Zhen explained. “They do high-energy physics research, not nuclear weapons.”

“High-energy particle accelerator and Large Hadron Collider, haven’t you seen it in the news?” Wang Ning displayed his extensive knowledge while simultaneously despising Old Bai’s ignorance.

“Europe? You even went to Europe?” Bai Zhen asked.

“To be on the safe side, we requested past experimental records from CERN,” River-Crossing Rat answered.

Bai Zhen put down the materials in his hands. “Impressive, you’ve done quite a lot in this half month.”

Hearing these words, all five people simultaneously became somewhat uncomfortable, as if their whole bodies were ill at ease. They unconsciously glanced toward Bai Yang’s room, then River-Crossing Rat lowered his voice and said: “That’s because we had Iron Hand Death Chase.”

“Iron Hand Death Chase?”

Bai Zhen and Wang Ning were stunned.

“Old Zhao?”

River-Crossing Rat nodded: “Teacher Zhao.”

“Why called ‘Iron Hand’?” Bai Zhen asked.

“Because he’s always making people clap,” Earth-Penetrating Rat’s expression was helpless. “Without iron hands, you couldn’t handle it.”

“Why called ‘Death Chase’?”

“You should see what he’s like when he’s pushing you to work,” Mountain-crossing Rat sitting on the same sofa still seemed traumatized. He hesitated before adding, “Even the donkeys in production teams didn’t work this hard.”

Bai Zhen opened another heavy black folder. On the first page was a striking red stamp—”Top Secret.”

“Bang!” He closed the folder immediately.

“This… we can read this for free?” Bai Zhen looked up and asked them.

“Read whatever you want,” Earth-Penetrating Rat nodded. “All the files brought here are ones you can and need to know about.”

Bai Zhen took a deep breath and solemnly opened the folder. Since taking the college entrance exam at age twenty, Bai Zhen had never encountered documents with such a high-security classification.

At this moment, he felt like an important person.

The folder contained a project plan, a thick volume roughly estimated at over a hundred pages.

“China Construction Eighth Engineering Bureau Co., Ltd.”

“Purple Mountain Observatory, Chinese Academy of Sciences.”

“Rock Physics Laboratory and Reservoir Geomechanics Group, Institute of Geology and Geophysics, Chinese Academy of Sciences.”

“That name’s long,” Bai Zhen muttered. “Nanjing Deep Rock Mechanics Big Science Project… Rock mechanics? That’s civil engineering, right?”

Wang Ning also curiously leaned over to look.

The two flipped through page by page, skimming, and roughly understood what this plan was about. It was a scientific project studying the impact of human engineering on Nanjing’s deep underground rock and soil structure, jointly planned by CAS Purple Mountain Observatory and CAS Institute of Geology, with construction to be handled by China Construction Eighth Engineering Bureau. According to the project plan, they would dig a deep hole underground in Nanjing to install a small unmanned laboratory for measuring rock layer stress conditions.

But Bai Zhen didn’t understand why they were showing this to him. He wasn’t involved in geology or civil engineering—why had a geological and rock mechanics research project mixed into the Amateur Radio Emergency Communications Command Center for Reversing the Future and Saving the World?

“This is another time capsule,” Earth-Penetrating Rat spoke up. “A super time capsule.”

Bai Zhen and Wang Ning were shocked.

“For the past half month, we’ve been researching methods of slow-time delivery. We’ve already proven that sufficient distance can escape the Great Filter, but sending time capsules into space has too many limitations—high cost, long preparation period, and restricted rocket payload capacity. So we’ve been actively researching other effective methods,” Earth-Penetrating Rat continued. “Director Wang, your previous experiment gave us inspiration—you embedded the time capsule in concrete within the wall.”

“To be precise, in the community gate,” Wang Ning pursed his lips. That time capsule was still in the main gate of Meihua Mountain Villa.

“This proves that besides sending time capsules into space, providing sufficient protection and fixation can also help them successfully survive the apocalyptic era,” River-Crossing Rat said.

“Is this also a means of weakening purposefulness?” Bai Zhen asked.

“It can weaken purposefulness,” River-Crossing Rat nodded. “By burying it deep underground and sealing it completely, it’s essentially no different from being sent to Mars orbit.”

“So what are you sending over this time?” Bai Zhen asked.

“A black box,” Zhao Bowen’s voice suddenly rang out.

Everyone turned their heads to see Zhao Bowen leaning against the doorframe of Bai Yang’s room with his arms crossed.

“What we’re sending this time is a black box,” Zhao Bowen walked over. “You know what a black box is? Every commercial aircraft carries one—it’s a recorder with a reinforced shell that continuously records internal communications. If the flight encounters a disaster, the black box provides the most direct and clear evidence for analyzing the cause. What we’re sending to the future is such a black box—it can tell us exactly what happened in the future.”

“A tape recorder?” Wang Ning asked.

“A robot,” Zhao Bowen said. “An AI system that will experience everything in the next twenty years for us, then tell us what the apocalypse was really like.”

“Hard to imagine,” Bai Zhen said.

In his mind, he pictured a small robot like WALL-E, hiding somewhere when disaster struck and staying hidden for twenty years until BG4MSR found it.

“It’s not as complicated as you imagine. Our era itself is already a highly developed information technology world, with massive data flows being transmitted between everyone’s phones every day. Whatever happens, news breaks on the internet immediately. So the black box doesn’t need to actively search for information—it just needs to listen, hidden deep underground, listening to the world’s movements. It has a keyword capture and filtering system. Once it detects suspicious information, it captures and stores it,” Zhao Bowen said. “This technology is very mature—government departments use similar methods for monitoring public opinion. We just borrowed a set—Tencent has it ready-made.”

“Then you’ll need to ensure its safety,” Bai Zhen said. “Ensure it can survive these twenty years and still work normally after the apocalypse.”

“That’s the hardest part. We can’t launch it into space, so the safest place is underground,” Zhao Bowen nodded. “Dig a deep hole and bury it.”

“This thing must be much bigger than a time capsule, right?” Bai Zhen asked. “From your description, you’d need at least a server room, plus data transmission lines, power systems, and cooling systems… Such a huge setup, you’re going to dig a hole and bury it all? You’d need to dig a very deep and large hole, then lower everything down—that’s a terrifying amount of work.”

“We’re borrowing something existing.”

“Existing?”

Zhao Bowen pointed at the ground beneath his feet. “Below us, under this city, there’s already a vast, interconnected tunnel system.”

Bai Zhen and Wang Ning suddenly understood.

Of course—beneath this city, there already existed a developed tunnel system, with hundreds of thousands of people flowing through it daily.

The subway.

“We thoroughly surveyed Nanjing’s subway system and, after considering various factors, finally selected two locations.” Zhao Bowen spread a map on the tea table and took out a marker to draw two circles, one at Gulou Park and one at Mochou Lake. “The Purple Mountain Observatory office building is above Line 4, and Mochou Lake station is on Line 3.”

Like most underground laboratories in the world, Zhao Bowen adopted the method of branching off from existing tunnels. Sichuan’s Jinping Mountain has the world’s deepest dark matter laboratory, branching off from a tunnel that crosses through the mountain, with 2,600 meters of rock overhead. Nanjing’s Line 3 has Jiangsu Province’s deepest subway station at Mochou Lake. Zhao Bowen would dig a small tunnel branching off from Line 3, with thirty meters of soil and rock overhead.

“We’ll dig one chamber under the Observatory and another beside Mochou Lake station, backing each other up. All equipment can be transported through the subway stations and installed in the chambers. After everything is arranged, we’ll seal the entrance from the subway tunnel,” Zhao Bowen said. “This way, we only need to dig a very small passage down from the surface, just big enough for one person to pass through—reducing the construction work by at least eighty percent.”

“What about the power system?”

“Nuclear batteries,” Zhao Bowen answered without hesitation. “Multiple nuclear batteries connected in series, lasting over twenty-five years.”

“And cooling?”

“The Mochou Lake station is next to the lake—we’ve designed water cooling channels,” Zhao Bowen answered. “The Observatory chamber is shallower and can be ventilated.”

This guy had already considered everything that needed considering.

In just half a month, how much had they accomplished?

“We have four groups working simultaneously, and Teacher Zhao is the second-in-charge of the entire project,” River-Crossing Rat said.

“I told you I’d bring an army,” Zhao Bowen declared.

Surveying everyone proudly: Am I awesome or what?

Bai Zhen: Awesome!

Wang Ning: Awesome!

Zhao Bowen: Applaud!

The whole room burst into enthusiastic applause.

“The official story for the whole project is that it’s a rock mechanics science project, but its actual purpose is secret. On the surface, we’re digging holes to install rock layer stress detection devices, but actually, it’s to bury the data recording system,” Zhao Bowen continued. “Once this system is sealed, only one person in the whole world can open it.”

“BG4MSR,” Bai Zhen said.

This truly was a super time capsule, utilizing countless human and material resources to create a space beneath Nanjing that only that girl could open.

“Among all of us, you treat her the best, Old Zhao,” Wang Ning said. “Gift after gift, from reaching the moon in the sky to searching the five oceans below.”

“When does this project start?” Bai Zhen asked.

“Start?” Zhao Bowen gave a cold laugh, saying in a tone that looked down upon all heroes: “It’s already finished.”