What used to be a two- or three-hour journey for Wang Lun and Li Ling took them over four hours to reach the campsite. By the time they arrived, the sun was already high in the sky. After putting their things down, Wang Lun took a pot to the stream to fetch water to prepare lunch. Li Ling tidied up the shelter, as it hadn't been inhabited for several days, and took out the dry grass used as bedding to air it out, also checking for any insects that might have gotten inside. At this time, Wang Lun returned with the pot full of water. He placed the pot aside, lit the campfire, put the pot on the fire, told Li Ling to keep an eye on it, and then went to fetch more water with two buoys. Li Ling then took out the seafood and fish that hadn't yet dried to dry. Once the water boiled, she added some wild vegetables she had picked during their rest stops along the way, and cut a piece of uncooked fish into the water. Wang Lun returned carrying two buoys filled with water. Seeing that lunch wasn't ready yet, he was relieved to finally be able to rest. Just as he sat down by the campfire, Li Ling finished tidying up and sat down as well. Wang Lun said, "After we finish eating, I'll go cut down some saplings to build a wooden fence. You can stay at the camp." Li Ling said, "I'll go too, two people can get it done faster." Wang Lun said, "No, you still need to stay at the camp and watch over the food, lest some animals eat it." Li Ling said, "But I can't just sit around doing nothing, can I?" Wang Lun thought for a moment and said, "Then you should dig the holes for burying the tree stumps first." Li Ling said, "Okay, where should we dig them? How many spaces should we leave?" Wang Lun then explained his plan to Li Ling. The wooden fence was mainly for temporary use, so it would only enclose the area near the shelter for the time being, leaving some space for movement. There would be a hole about one meter apart, mainly on the two flat sides. The two higher grounds wouldn't need a fence for the time being; they would just use the height difference to block them. The people below probably couldn't get up, and the people above could probably jump down easily, so he also planned to put some thorns on the edge of the higher ground and some short spears on the bottom, so that if anyone jumped down, they would be impaled. After listening to Wang Lun's explanation, Li Ling basically understood. Looking at the platform she was living on, which was about seven or eight meters wide, she figured her workload wasn't too heavy. Wang Lun said, "You're overthinking it. Your workload is huge. It's not just digging pits; you also need to bury short spears behind them, making sure they're densely packed. If you don't have enough spears, just keep digging the pits and do the rest at night." Li Ling asked, "Why not build a fence on the cliff?" Wang Lun said, "I've thought about it. It's difficult to dig pits on the cliff edge, and it's also difficult to seal the edges, so it's better to just set a trap below and let it jump down. Besides, there are thorns above; it has no choice but to jump." Li Ling asked, "How wide should we make it?" Wang Lun said, "About four or five meters, about the same width as this shelter. After all, this is temporary; we'll use it for now, and we won't need it anymore once the fence is finished in a few days." Li Ling felt a sense of security just thinking about the half-meter-thick fence. While the two were talking, the stewed fish with wild vegetables in the pot was ready. Because they had done a lot of physical labor that morning, they finished the whole pot.

After finishing his lunch, Wang Lun put down his bowl, picked up his spear and machete, and went into the woods. Li Ling cleaned up the pots and pans and started digging holes at the shelter. At first, she felt it was manageable. But after digging a few holes, Li Ling needed to rest, as she was already exhausted from carrying so much stuff that morning. She had originally planned to finish slowly and wait for Wang Lun to return, but then she remembered that Wang Lun was carrying a heavier load than her, and had been walking behind her, putting most of the weight on her back. Now that he was off cutting down trees, she got up and persevered, finishing digging the tree stump holes before finally resting. While resting, she realized she was almost out of cooled boiled water, so she put the pot on the campfire to boil some more.

Wang Lun, having chosen a spot in the woods surrounded mostly by small trees, began chopping down trees. He didn't care how many he cut, just kept chopping until he couldn't carry them anymore, as he needed them for the fence, the wall behind, and the earthen house. So he hurried off to chop. Along the way, he collected some vines he encountered. When he felt he had chopped enough, he bundled them up, tested their weight—they were indeed heavy, but thankfully, he could carry them. He then picked up his tools and returned to camp.

Back at camp, Wang Lun saw Li Ling digging a hole behind the shelter, burying short spears. He put down the sapling he was carrying and called out, and Li Ling came over. Wang Lun said, "Don't work so hard, take a rest." Then, without further ado, he pulled Li Ling to sit down and poured her a bowl of water. After resting for a while, Wang Lun said, "I'll demonstrate how to bury the stakes first. I have to go out again later. You can finish burying the stakes first, and if I'm not back by then, tie up the fence." Li Ling asked, "What are you going to do again?" Wang Lun said, "I'm going to collect some vines and cut some thorns." Li Ling nodded. Wang Lun added, "Don't overwork yourself, rest more. If you're not finished, I'll finish when I get back." Li Ling said, "I know." So Wang Lun led Li Ling to a dug hole, took out a sapling, and forcefully stuck it into the hole, then filled it with soil. Wang Lun said, "That's it. Just tie some branches horizontally at the back, and that'll be about right." Seeing that Li Ling understood, Wang Lun picked up his machete and spear and went out.

Fortunately, while searching for vines, Wang Lun had come across a patch of thorns, so he went there to cut them. He chopped down a large pile, carefully tied it up, and prepared to drag it back. However, this darn thing was incredibly difficult to drag; it kept getting caught on the trees on either side. Wang Lun struggled to drag the pile of thorns to the earthen cliff behind the shelter, and then spent some time arranging it. Seeing that Li Ling was still burying tree stumps, he told her to rest more, and then went back to chopping thorns. After three trips, he felt he had done enough. The later trips were easier to drag than the earlier ones, since he had already traversed the area once.

The last time Wang Lun dragged the thorns back to camp, he saw Li Ling tying up the fence, so he went over to help. Li Ling said, "You've just gotten back, go and rest for a bit." Wang Lun said, "No rush, let's finish tying this part first before resting." Seeing Wang Lun say this, Li Ling had no choice but to speed up her work. And sure enough, two people are much faster than one person, and they finished tying it up in no time. At this point, the fence was basically completed, more than two meters off the ground, with a stake every meter, a horizontal branch 30 centimeters below the meter, and another branch half a meter above. Wang Lun said, "Let's rest for a bit, we'll wrap some thorns around it later." Li Ling nodded.

The two returned to the campfire, each poured a bowl of water, and were drinking. Suddenly, Li Ling said, "We're running low on firewood; we probably won't have any left tomorrow." Wang Lun said, "Oh, okay, I'll go gather some more from the jungle later." Li Ling looked at the sky, estimating it was probably around four in the afternoon, and said, "Why don't you go gather firewood first? I'll tie up the thorns myself." Wang Lun said, "That's fine, but be careful; those thorns really hurt." Li Ling said, "I know, I'm not a child." Wang Lun laughed and said, "Who says a 300-month-old baby isn't a child?" Li Ling nudged Wang Lun and said, "Who's 300 months old? I'm not!" She then got up to tie up the thorns. Seeing this, Wang Lun smiled, then picked up his machete and spear and went to gather firewood from the jungle.