Just as Chen Hao's hand touched the airlock door handle, Nana's voice came through the earpiece: "The internal pressure has been balanced, you can open it."

He pushed open the door. The light outside was still blue, but it wasn't as glaring anymore. The ship was anchored at the edge of the safety zone, its main engine whirring at a low frequency, as if it were dozing off. Karl was already waiting on the deck, carrying two sealed boxes. Seeing them come out, he put the boxes on the ground: "Everything's ready, just waiting for the two of you."

Susan poked her head out of the control room: "The sample transfer vehicle has arrived. The handover must be completed within ten minutes, otherwise the temperature control system will not be able to handle it."

Chen Hao took off his helmet, his hair sticking to his forehead with sweat. He wiped his face and said, "I thought I could lie down until tomorrow."

"Dream on." Carl patted him on the shoulder. "You were brave when you went in, but you'll have to work when you come out."

Nana didn't speak, but simply handed the data storage device in her hand to Susan. It was a small, silver-gray cube with several scratches on its surface, as if it had been rubbed against a rock wall.

“This is a complete scan record of the interior of the sealed chamber,” she said. “It includes energy fluctuation frequencies, structural material analysis, and… the original waveform of that symbol sequence.”

Susan took it and gently touched the connector with her fingers: "It still works?"

"Yes," Nana nodded. "The core is undamaged."

The four of them walked together toward the cabin. The passageway was narrow, the lighting dim, and their footsteps mingled together, sounding somewhat chaotic. Chen Hao walked at the back, glancing back at the sea as he went. The crack was still there, its blue light flashing intermittently, like blinking.

"Are we really going to shut it off?" he asked.

“You pressed the reset button yourself.” Carl didn’t even turn his head. “Don’t tell me you’re now doubting your memory.”

"It's not that I don't believe in myself," Chen Hao muttered, "it's that I don't believe my luck can be this good."

Upon arriving at the control room, everyone sprang into action. Susan inserted the memory into the read slot, and a progress bar immediately appeared on the screen. Carl began disassembling the inspection robot, storing the battery and camera separately. Nana connected to the base network and uploaded backup data. Chen Hao pulled out his notebook, sat down in a chair in the corner, and began writing a summary.

"Hey," he looked up, "does anyone remember what we said before we came in?"

Nobody paid him any attention.

“I said, ‘We’re going to open the door,’” he answered himself. “Then click, the door opened. It was so smooth, it sent chills down my spine.”

“Because you didn’t bring any explosives in.” Carl unscrewed the last screw. “If you had blown it up, we’d be collecting parts on the seabed right now.”

“That’s not the point.” Chen Hao closed his notebook. “The point is, why did it let us in? The creature didn’t stop us, the mechanism wasn’t locked, and the alarm didn’t even go off. We just stuck a piece of paper on it, and it opened the door—like scanning a QR code to pay.”

Nana stopped what she was doing and turned around: "Based on the existing data, the triggering mechanism does indeed rely on 'silent approach' and 'symbol matching.' But the deeper logic has not yet been deciphered. I suggest keeping the hypothesis: this civilization rejects proactive aggressive signals and prefers low-interference contact patterns."

"Translate it into human language," Chen Hao said.

“Just don’t make a sound,” Susan chimed in. “If you yell and rush over, it might just collapse. If you come quietly, it’ll show itself.”

"So we didn't win because of skill," Chen Hao grinned, "we won because of our social anxiety."

No one laughed, but the atmosphere relaxed a bit.

Two hours later, the ship docked. Base personnel were already waiting at the pier, dressed in protective suits and pushing transport vehicles. The handover process was quiet and orderly. Samples were packed, equipment was returned to its place, and data was synchronized. Chen Hao stood at the entrance of the command center, watching the last box of materials being transported away, then turned and went into the conference room.

The projector on the table was lit up, displaying a hologram that Nana had brought up: a stone slab rubbing, blue light distribution, and the structure of the secret room.

"Is everyone here?" He sat down. "Then I'll begin."

“One minute each,” he said. “Say what you think is most important. Susan, you go first.”

Susan cleared her throat: "I collected three types of microbial samples outside the sealed room. Their energy metabolism is entirely dependent on that blue light. This means that there may be a closed ecosystem in this area, independent of the sunlight cycle. If it can be replicated, it would be a breakthrough in extreme environment survival technology."

“Karl?”

“The alloy layer on the rock wall,” Carl pointed to the screen. “I scraped some back. The composition analysis isn’t finished yet, but preliminary results show that its compressive strength is seven times that of titanium alloy, while its weight is forty percent lighter. It’s enough to build submarines and spacecraft.”

Where is Nana?

“A basic reference table for the symbol system has been established,” she said. “The currently translatable parts indicate that this civilization once possessed space-folding technology for deep-sea migration. They called themselves ‘Silent Ones,’ meaning ‘people who move in silence.’”

Chen Hao nodded: "It's my turn. I think the most amazing thing is not what we discovered, but that we survived. I didn't die, Nana didn't explode, Carl didn't go on strike halfway through the repair, and Susan didn't go crazy because she hadn't had coffee for too long. That in itself is a miracle."

Susan rolled her eyes: "I drank three cups of instant coffee yesterday."

“That’s even more terrifying.” Chen Hao waved his hand. “In short, this operation proved a few things: First, although our team is poor, we are not cowards; second, don’t underestimate me just because I’m usually lazy, I still dare to charge forward when it matters; third, Nana is more reliable than I thought.”

Nana glanced at him and said, "Thank you."

"Don't misunderstand," Chen Hao quickly added, "I just meant I didn't hold anyone back this time."

The meeting continued. The participants began discussing the procedures.

“Next time we go to a similar place,” Chen Hao said, “I can’t decide whether to go in or not by myself. It’s too risky. We need two people’s signatures, like me and Nana, or Calga and Susan. Anyway, I can’t let one sentence drag the whole team into this mess.”

“Agreed,” Carl said. “And we need to prepare two sets of detection equipment in advance. If I hadn’t modified the robot this time, we wouldn’t even know what the door looks like.”

“There are also signal response files,” Nana added. “I have compiled the timeline of this magnetic field anomaly and entered it into the early warning model. In the future, when similar fluctuations occur, the system will automatically suggest avoidance routes.”

Susan jotted down a few notes, then suddenly looked up: "Have you ever considered that the secret room is just the outer layer?"

"What do you mean?" Chen Hao asked.

“Behind the door was just an empty room and a whiteboard,” she said. “No signs of life, no remains, and no real ‘treasure.’ It was more like… a guard post. The real treasure is deeper inside.”

No one spoke.

Carl slowly began, “The alloy microparticles I extracted were peeled from the inner rock wall. That kind of material wouldn’t be used casually for doorway decorations. It should be part of the main structure.”

Chen Hao stared at the projection for a while, then suddenly laughed: "So, we went through all that trouble to open a door, only to find it was a guardhouse?"

"More or less," Susan nodded.

“Then we definitely have to go.” Chen Hao stood up. “If the guardhouse is this valuable, how many gold bars must the finance office be hiding?”

"This isn't a treasure hunt," Nana cautioned.

“I know,” Chen Hao grabbed his coat, “but who wouldn’t want to know where the boss’s office is?”

The meeting ended. All data was archived, and the report was submitted. Nana disconnected the external connection, and the device entered standby mode, with only one indicator light flashing faintly. Susan and Carl went to the lab together to arrange sample storage; the corridor lights cast long shadows on them.

Chen Hao returned to his room and placed the notebook on the table. The cover read "650th Trip," but there weren't actually that many trips. He randomly flipped to a page, which had a crookedly drawn door and the words "The Silent Can Reach It" written next to it.

He stared at it for a few seconds, then closed the notebook.

The next morning, at the base restaurant.

Chen Hao sat down with his plate and took a bite of the cold fried egg.

Susan sat down next to me: "Last night I dreamt that the door opened again."

"Then what?"

“A figure came out, dressed in what looked like a diving suit, but without an oxygen tank. He nodded at me, and his lips moved.”

"What did you say?"

“I can’t see clearly,” she frowned, “but I feel like he’s saying ‘again.’”

Chen Hao chewed on his egg without saying a word.

Carl walked by and put down a cup of black coffee: "Nana just sent a message saying that the automatic scan last night detected a new residual signal. The frequency was very low, lasting for thirty-seven seconds, consistent with the first pulse received."

Where did it come from?

“It came from the seabed,” Carl said, looking at him. “Just six hours after we left.”

Chen Hao put down his fork, the metal making a crisp sound as it hit the plate.