The ground shook again.

Chen Hao's hand trembled, and the terminal almost fell to the ground. He quickly stuffed the device into his backpack and zipped it up. The light in the secret room was still flickering, like a light bulb running out of power, turning on and off.

"Is the data transmission complete?" he asked.

Nana stood in front of the stone tablet, her finger tracing the last line on the scanner. "Holographic backup complete, no original data missing."

"Then why aren't you running?" Chen Hao turned and walked towards the door, his footsteps kicking up a cloud of dust.

Susan had already packed the seed bags and tools and slung them over her shoulder. Carl was securing the formula board with straps, his movements steady, but sweat beaded on his forehead. The tremor earlier had caused a stone to fall from the corner, hitting him just shortly after.

"Let's go." Karl said, and was the last to leave the secret room.

Chen Hao glanced back. The door, covered in symbols, was slowly closing, the gaps getting smaller and smaller, until finally, with a click, it shut completely. The light disappeared, and the passage fell into darkness.

The four turned on their headlamps and retraced their steps.

The passage was narrower than when they came, with tiny cracks in the rock walls on both sides, and loose rocks constantly falling from above. Nana walked at the front, holding the sensor to her chest, the green line on the screen jumping steadily.

"The structure is temporarily stable," she said. "It is expected to hold for at least two hours."

"So, we have two hours to escape?" Chen Hao gasped for breath. "That's really reassuring."

No one answered. Footsteps echoed in the corridor, rhythmic and steady.

When he emerged from the underground entrance, the sky outside was gray. A wind blew in from behind the ruins, carrying the smell of rust mixed with earth. Chen Hao wiped his face and found his palms were sweaty.

The four people stopped in the open space.

The backpacks were piled up together, and we began to take inventory.

Twelve earthenware jars, all sealed, were placed in a shockproof box and carried by Carl. The seed bags were wrapped in three layers, which Susan was in charge of. The formula board, rubbings, tools, and parts were all packed into waterproof bags, and Chen Hao carried the largest box, his shoulders aching from the weight.

"This thing is heavier than the cured meat my mom stocked up for Chinese New Year," he muttered.

“Your mom stocked up on 30 jin of cured meat for the New Year,” Nana said. “This is 28 kilograms.”

"Do you remember something I casually mentioned?"

"My memory modules will not miss any valid information."

"Do you remember me saying I'm afraid of snakes?"

“I remember. During your seventh field training session, you screamed for seventeen seconds, reaching a volume of ninety-two decibels.”

Chen Hao rolled his eyes: "Can't you forget something?"

Susan squatted down to check the rope knots: "Stop joking around, have you decided on the route yet?"

Nana unfolded the topographic map projection. Blue light floated in mid-air, marking a winding route.

“Returning the way we came is too risky.” She pointed to a red area on the left. “There is frequent activity from biological thermogenic sources, with at least three adults wandering around. We recommend detouring through the northwest canyon, crossing the edge of the swamp, entering the dense forest, and then returning towards the base.”

“Twenty kilometers longer.” Carl frowned.

"But the safety factor has increased by 63 percent."

“Then let’s go around.” Susan stood up. “I don’t plan on putting on another escape movie on the way back.”

Carl nodded and memorized the map. Chen Hao sighed and slung the suitcase back over his shoulder.

"Fine. But if anyone says halfway through, 'Actually, there's a shortcut,' I'll lie down and refuse to go any further."

Before setting off, he stood at the entrance of the ruins for a few seconds.

The stone was cold and hard, its patterns weathered by the wind for thousands of years, yet it remained there. They couldn't take what was inside with them, but they photographed it, recorded it, and remembered it.

“What we’re taking back this time,” he said softly, “is not just a few pieces of paper or stones. It’s something that can keep people alive.”

The others didn't speak, but they all paused for a moment.

Then, they turned around together.

The journey home begins.

The team formed a triangular formation. Nana was in front, holding a detector and staring at the screen. Carl and Susan were on either side, one holding a gun and the other a knife. Chen Hao was in the middle, carrying the heaviest bag, walking slowly but without falling behind.

Stop every twenty minutes.

Nana scanned the surroundings to make sure no heat sources were nearby. Susan checked the footprints for signs of being followed. Carl measured the wind direction to determine the path of the odor. Chen Hao was in charge of providing water and food, and also telling corny jokes.

"Do you know why robots never get lost?" he said, chewing on a compressed biscuit.

"Because of the built-in navigation?" Susan asked.

"Wrong. Because they never ask for directions, and they can claim they're following a plan even if they wander off on their own."

Nana turned around and glanced at him.

"Your sense of humor is still at a fifth-grade level."

"But you still listened."

"I'm just assessing the extent of human language degradation."

"Do you have to make the atmosphere so serious?"

“Excessively high sound frequencies can cause rock strata to resonate,” she said. “That statement just now caused the infrasound reading to rise by 0.7.”

Chen Hao opened his mouth, but swallowed the rest of his words.

The procession continued forward.

As they crossed the canyon, the wind picked up. The scree slope became loose, and they slipped with every step. Chen Hao nearly fell, only managing to steady himself thanks to Karl's help.

"Thanks." He patted the other person on the shoulder.

“Be careful next time,” Carl said. “If you break something, who’s going to carry that pile of junk?”

"I can walk," Chen Hao snorted. "Fat as I may be, I'm strong."

We didn't eat lunch, just ate energy bars. It was too dangerous to start a fire. We also limited our water intake, taking turns, just a sip each.

At 3 PM, we entered the edge of the swamp.

The ground was soft, and you'd sink in if you stepped on it. Nana tried several times with a probe and found a barely passable route. Everyone moved along the base of the grass, afraid to jump for fear of disturbing something.

A waterbird suddenly took flight, fluttering and soaring into the sky.

All four of them lay down at the same time.

After waiting for a few minutes, nothing happened.

"What a scare!" Chen Hao got up, his pants covered in mud.

"Don't move." Nana suddenly raised her hand.

Her screen lit up briefly.

Fifteen meters ahead, the ground trembled slightly.

It wasn't an animal stepping on it; something was moving underneath.

“Empty?” Susan whispered.

“The groundwater flow has changed course,” Nana adjusted the parameters. “Or it could be a precursor to a small landslide.”

"Can you still walk?"

"Yes, but we must speed it up."

They quickened their pace, skirting the edge of the hard ground. Chen Hao's suitcase scraped against a dead tree, making a soft "crack" sound.

Everyone stopped.

In the distance, the wind rustled through the reeds.

A few seconds later, Nana waved her hand: "Continue."

As we emerged from the swamp, the sun was setting.

We've arrived at the woods.

Tall trees blocked out the sun, dimming the light. Nana activated night vision mode and led the team through.

Chen Hao's breathing was a little heavy, and sweat streamed down his neck. He didn't complain of being tired, but his movements slowed down each time he switched shoulders.

"How about I help you divide some?" Susan asked.

"No need," he waved his hand. "I can carry it. Besides, this contains the menu for the future cafeteria."

"You're still thinking about eating?"

"Isn't the point of living to have a good meal?"

Deep in the woods, the ground begins to slope uphill.

This is the edge of the new area; twenty kilometers further ahead lies the boundary of the safe zone. The base is in sight.

But none of them relaxed.

“One last check.” Nana stopped and scanned the surroundings.

The green line is stable and there are no abnormalities.

Susan examined the footprints and confirmed that there were no repeated tracks.

Karl wiped the barrel and reloaded the gun.

Chen Hao sat down against the tree, took a few breaths, and looked up at the sky.

Stars began to peek out from between the leaves.

"What do you think the base is like now?" he asked.

“Someone must be fixing the solar panels,” Susan said.

"The canteen is probably making potato soup again."

"The radio plays that old song every day."

"I hope the water heater still works."

A brief silence.

They all wanted to go home.

"Let's go." Carl patted Chen Hao on the shoulder. "We still have to drive five kilometers before dark."

The troops regrouped.

Nana was in front, the detector glowing faintly.

Chen Hao stood up and adjusted the straps of his backpack.

I took a step and my foot slipped.

He reached out to brace himself, his palm landing on a loose stone slab.

A hollow sound came from under the stone slab.