The river water was rushing, and Chen Hao was still standing on the bank, his folding shovel still in his hand.

He stared at the metal frame leaning against the ruins on the opposite bank, with the fallen log that Nana had scanned earlier at his feet. The trunk wasn't thick, but it was long enough; laid horizontally, it would be enough to build a bridge.

"You just said you didn't have enough materials," Nana said, looking at him. "What are you planning to do now?"

"We don't have enough materials." Chen Hao squatted down and touched the bark with his hand. "But I can make do."

He looked up at her. "Could you sweep this area again? See if there's anything more solid."

Nana raised her hand, the light screen unfolded, and the data scrolled for a few seconds before stopping.

“There are no intact building materials within a 500-meter radius,” she said. “The best available material is still the fallen timber, which can be reinforced with surrounding steel bars and sheet metal.”

“I knew you would say that.” Chen Hao stood up, walked to the steel bar that was stuck diagonally in the ground, grabbed it with both hands, and pulled it upwards with force.

The steel bar wobbled twice, but didn't move.

He changed his angle again, braced his knees against the ground, gritted his teeth, and pulled again. This time the steel bar loosened a little, making a squeak sound, and was slowly pulled out.

“This thing is used as an anchor,” he said, panting. “One end is fixed on this side, and the other end is thrown to the other side to get stuck.”

“The soil density on the opposite bank is insufficient to form an effective anchor point.” Nana came over to inspect the steel reinforcement. “I suggest using U-shaped bends to enhance the embedding stability.”

"You mean you want to break it into a hook?"

"correct."

Chen Hao glanced at the length of the steel bar, nodded, and said, "Okay, then bend it."

He stepped one end of the steel bar into the crack in the stone, and used a folding shovel as a lever to press down on the other end. The metal emitted a harsh scraping sound and slowly bent into a crooked U-shape.

"It's a bit ugly," he said, "but it works."

Nana took the steel bar and walked to the riverbank. "I will test the load-bearing capacity of the soil on the other side and determine the best insertion point."

She jumped onto a rock near the water's edge, her optical lens flashing slightly. A few seconds later, she nodded: "There's a rock base supporting this spot. Driving it in 30 centimeters will ensure it doesn't slip."

"Then you plant it, I'll hold the tree."

The two of them worked together to drag the fallen log to the shore. One end of the trunk was placed in the U-shaped groove of steel bars that Nana had secured, and the other end was wrapped with sheet metal and tied to a large rock on the shore.

“The bridge is only forty centimeters wide,” Nana assessed. “Passing across it requires you to be close to the ground with your limbs and keep your center of gravity low.”

“I know.” Chen Hao looked at the water. “I’m not afraid of heights, I’m just afraid of falling in and taking a cold shower.”

"The river water is 12 degrees Celsius. Soaking in it for more than three minutes may cause muscle cramps."

"Thank you for reminding me of something I don't want to hear."

Nana didn't respond. She climbed the tree trunk first, and the machine, with its stable center of gravity, walked step by step to the other side. She turned around and stood still, gesturing with her hand: "The structure is stable and can bear a weight of over 100 kilograms."

"Then why didn't you say so just now?" Chen Hao asked with a wry smile.

"I had already completed the test before you asked the question."

"Do robots hold grudges?"

"I'm just stating the facts."

Chen Hao took a deep breath and climbed onto the tree trunk. He gripped the rough bark with both hands, his knees braced against the edge, and inching forward. Water rushed down from below, splashing and wetting his trouser legs.

Halfway there, the tree trunk swayed slightly.

He stopped immediately. "Don't shake it. I don't have insurance."

"Wind speed increased by 0.5 levels," Nana said from the other side. "Please increase your movement speed."

"You make it sound so easy. I'm not a spider."

He continued crawling forward and finally touched the muddy ground on the other side. As soon as he landed, he lay down, opened his arms, and said, "It's so good to be alive."

Nana looked down at him and said, "You took three minutes and fourteen seconds to cross the river, which is less efficient than expected."

"You even kept a timer?"

"All actions are being recorded."

"Could you please not tell me these numbers next time? They're affecting my mood."

Nana didn't answer, and turned to walk towards the factory.

The collapsed warehouse was just ahead; half the roof had collapsed, and the walls were cracked like jigsaw puzzle pieces. Broken bricks and beams were piled up at the entrance, blocking it.

"We need to move this pile of stuff aside before we can get in." Chen Hao stood up and dusted himself off.

“No need.” Nana stepped forward and switched the optical lens mode. “There is a structural crack in the right wall, wide enough for us to pass through.”

She squeezed through a narrow gap, and footsteps could be heard from inside. A few seconds later, there was a click from inside the door, as if the latch had come loose.

Then, half of the rusty iron door was pulled open from the inside.

Chen Hao was stunned. "You can pick locks?"

“I didn’t unlock it,” Nana said as she stepped out. “I just pushed a loose latch inside.”

"Oh." He scratched his head. "I thought you had some hidden ability."

"All my functions are registered in the database."

"That's pretty professional."

The two walked into the warehouse together. It was dimly lit, but they could see neatly stacked metal supports in the corner, each with a numbered label, and bundles of bolt components and rolls of waterproof canvas next to them.

“These are all the things we need.” Chen Hao walked over and touched the surface of the bracket. “It’s not rusty or deformed.”

"The material is high-strength alloy steel," Nana confirmed after scanning. "It meets the standards for triangular supports and can be used for load-bearing reinforcement of the base."

"Not bad luck." Chen Hao grinned. "Looks like God didn't want me to make a wasted trip today."

He walked around the shelves and found several sealed boxes. When he opened them, they were full of connectors and tool kits.

“These things will come in handy when we get back.” He picked up a bag. “It’s much better than expecting Carl to rummage through the trash.”

Nana walked towards the control panel area. There was a small table there, with a drawer half open. She pulled out the bottom drawer and took out a paper document.

"What is this?" Chen Hao asked, leaning closer.

“Regional Geological Stability Assessment Briefing,” she read the title. “Printed three days before the earthquake.”

"There's such a thing?" He took the document and flipped through a few pages. "Underground water veins, fault lines, earthquake focal depth... Isn't this just a map cheat?"

“This data contains a model predicting recent geological activity on this planet,” Nana said. “It can be used to avoid high-risk areas in the future.”

"That's great." Chen Hao stuffed the documents into his backpack. "I won't have to guess anymore."

He looked around and said, "There's a lot of stuff. We need to find a way to get it back."

“It can be used to make a simple sled.” Nana pointed to a pile of scrap iron sheets. “Using steel pipes as axles and iron sheets as the platform, it can bear a load of up to 200 kilograms.”

"Your head is like an encyclopedia."

"I simply retrieved common transportation options."

"Alright, let's get started."

They began disassembling the materials. Chen Hao was in charge of cutting the sheet metal, while Nana used wire to make the frame. In less than half an hour, a flatbed trailer with handles was formed.

"It's a bit ugly," Chen Hao patted the car body, "but it should be fine for hauling things."

They loaded the metal frame, bolt pack, and canvas roll onto the vehicle one by one, and finally placed the document on top and secured it with rope.

"Is everything ready?" Chen Hao asked.

"The inventory of supplies is complete," Nana said. "A total of twelve support frames, five boxes of connectors, some auxiliary materials, and one document."

"Then let's prepare to head back."

He was about to push the cart when he suddenly stopped. "Wait."

"What's wrong?"

Chen Hao squatted down and pointed to a piece of sheet metal at the bottom of the trailer, "This piece is a bit warped, it'll easily fall apart on the road."

He readjusted the position, wrapped the wire around the neck a couple more times, and tightened it.

"Alright." He stood up. "Now you can really go."

Nana walked ahead to scout the way, while Chen Hao pushed the cart behind. As they exited the warehouse, sunlight peeked through the clouds, illuminating the metal frame of the cart and casting a bright reflection.

"Do you think Karl will say we've been slacking off and not doing any work when we get back?" Chen Hao asked with a smile.

“Based on past conversations,” Nana turned to look at him, “he’s more likely to suspect that you stole his mission.”

"And what about Susan?"

"She usually keeps quiet until a problem is discovered."

"That's true." Chen Hao snorted. "Smart people always strike last."

They walked back along the same route and came to the riverbank. The bridge was still there, the tree trunks hadn't been washed away, and the anchor points at both ends were intact.

"I'll go first," Nana said.

She walked across the bridge with ease, and waved after stopping.

Chen Hao left the trailer on the shore and climbed up alone. This time he was faster and didn't stop midway, successfully reaching the other side.

He glanced back at the bridge. "This dilapidated bridge is actually holding up."

"The structural design is reasonable," Nana said, "and it has not been overloaded."

"Could you make it wider next time?"

"Modular splicing bridge decks can be used next time."

"It's too late for you to say this now."

They reassembled the trailer, ready to continue their journey. After taking only a few steps, Chen Hao suddenly stopped.

“No,” he said.

Nana turned around. "What's wrong?"

Chen Hao stared at her feet. "When you came over just now, did you step on that U-shaped steel bar?"

Nana looked down. "Yes. I used it to test the load-bearing capacity."

“But I remember…” Chen Hao frowned, “the U-shaped opening I made was facing upwards.”

He walked over and squatted down. The steel bar was stuck in the ground, with the U-shaped groove facing down.

“It rolled over,” he said. “Nobody touched it; it can’t roll over by itself.”

Nana squatted down to check the insertion angle.

The river is still washing over the stones on the bank.

The wind blew through the broken sheet metal, making a slight clicking sound.

Chen Hao reached out and touched the edge of the steel bar.