Shanquan opened the medicated oil bottle. In order to pour exactly on the side of the hollow, the position of the bottle should be as close to the floor as possible. Therefore, he had to adjust his body in a prone position so that he could pour the oil from a distance of only a few centimeters from the floor. Yixiong and Xinxiu promptly stepped aside to make room for Shanquan.

Like before, Yingyue was looking up from above. So that he wouldn't be dazzled by the flashlight, Shanquan forbade Yingyue to glare from the front. He told Yingyue to sit on his back so that the flashlight could be directly above Shanquan's head. From above Shanquan's head, the flashlight shone straight into the hollow.

Shanquan carefully poured the liquid. After that, he closed the bottle and placed it beside where he was kneeling. He had to start prying now before the box was dry again. It was still difficult, but he felt there was some progress. Slowly but surely, he managed to pry out the wooden box. Shanquan sat on the floor with a sigh of relief. Suddenly Shanquan remembered something. When he was in a prone position on the floor, he felt the coldness of the floor touching his chest and stomach.

Maybe I should use this medicated oil to warm my stomach and chest a little.

After thinking so, he quickly asked Yingyue's permission to use the medicated oil. The girl nodded. She was even willing to help Shanquan. However, Shanquan chose to apply the medicated oil himself.

Meanwhile, Yixiong and Xinxiu scrutinized the small wooden box. They put the wooden box on the table. After Shanquan finished applying the medicated oil to his stomach and chest, he soon joined his two colleagues to observe the wooden box.

"It's a Wooden Box Puzzle." Shanquan took a deep breath. They get excited too soon. It turned out that their struggle was not over. It took a further effort to open the wooden box.

Yingyue also observed the wooden box. "May I try to open it?"

"Of course." Shanquan smiled. He handed the box to Yingyue, who observed it at once.

"This box is very nice," Yingyue said. "There are hardly any gaps between the sides of this box. If we weren't careful, we'd think this box came from a log carved into a box. The joints between the sides are very smooth."

Yingyue's face was grave as she checked the box. Shanquan was really in awe of Yingyue. That girl really wasn't an ordinary girl.

Perhaps I should learn a lot from this girl instead!

Yingyue frowned. The girl groped each side of the box. She tried to push each side of the surface of the box. Shanquan knew that it usually took a few steps to open a box like that. Her slender fingers traced the box's surface carefully as if to persuade the box to slide one side promptly so that the box could be opened.

"Wow!" Yingyue cheered.

She began to push down one side of the box. In Shanquan's view, Yingyue's way of opening the box was very similar to the movements to solve a Rubik's cube puzzle. Shanquan guessed the girl would not take long to complete the Rubik's cube.

Yingyue shifted the top side of the box to the side. The upper side surface was indeed slightly exposed. Yingyue's fingers moved to the bottom of the box. She pressed the underside up or, rather, pushed into the box. Because it was pressed towards the top, the top side was pushed up. At that time, the top surface of the box really looked like a small coffin lid.

After that, Yingyue only had to slide the lid to the right. The lid slid to the right until it was completely removed from the box. Inside the box, there was a small compartment that could become a place for storing small items. Yingyue smiled. Cheerfully, she then put her finger in the box. Yingyue took out a key from inside the box. She quickly gave it to Shanquan.

Extraordinary! Where did this girl learn something like this?

They all then walked towards the door on the west wall. Shanquan didn't know if the key he was holding was really the key to the west door. But he had to try. Shanquan put the key into the hole in the door that had no handle. Shanquan tried to turn the key, and it worked. Even though it's a bit dragging, the lock rotates. After the sound "click," the key stuck. Shanquan couldn't turn the key any further.

The iron door was without a handle, so they couldn't open it right away. Shanquan, Yixiong, and Xinxiu simultaneously pushed the door with all their might. The door leaf moved inward. The door opened little by little. Until they finally managed to open the door completely.

The door on the east side had indeed opened. Behind the door, there was no other room. There was only one dark alley. Yingyue was standing right behind Shanquan. Instantly, Shanquan could feel Yingyue's body pressed against his back.

"Are you afraid?" Shanquan said the question without looking back.

"Absolutely not." The girl's voice sounded so steady.

Shanquan had no idea how long the passage was. The pitch-black atmosphere could only allow them to see within a very limited range. Although Shanquan used a flashlight to highlight the inside of the passage, the part of the passage they could see was no further than six meters. Shanquan was contemplating whether or not to go in now to explore the underground passage.

"Dahge, be careful," Xinxiu shouted as Shanquan started to walk down the hallway.

Hearing Xinxiu's words, Shanquan pulled back the leg he had just stepped on. Yingyue, who was standing right behind Shanquan, collided with Shanquan's body when Shanquan suddenly retreated backward. Shanquan immediately turned around. Reflexively, he held Yingyue's body. Shanquan was worried that Yingyue might lose her balance and that she might fall. The two of them then took two steps back from the already open door.

"I can feel a stream of air coming out of this open door. So I don't think there's a problem with the oxygen levels in the hallway in front of us," Yixiong said.

Shanquan shone his flashlight towards the corner of the room from which they had come. The two oxygen cylinders were still sitting there. He looked at Yixiong and Xinxiu. "You two wait here. I will enter the hallway with Yingyue."

After saying that, he took Yingyue's hand and stepped forward. Shanquan could hear the girl's steps. He knew that she was trying hard to keep up with his steps.

Ah! I shouldn't move too fast.

"Dahge! Wait a minute!" Yixiong said in a loud voice.

Shanquan stopped in his footsteps. He turned around. Even though it was dark at that time, Shanquan was sure that Yixiong's eyes were staring at him intently.

"Are you guys really going in there?" Yixiong's voice sounded confused.

I know Yixiong must be wondering why I led Xiaotian into the dark alley. Isn't that very dangerous?

"Of course I'll go in there. Isn't this our goal?"

"I mean, is it enough just to bring a flashlight? Wouldn't it be better if we brought a bigger lamp, like the Kerosene Pressure Lantern." Yixiong said.

Uh? He wasn't worried about Xiaotian? Ah! Maybe I'm the only one who worries so much that I don't want to leave her alone!

"Do we have a Kerosene Pressure Lantern we can still use?"

"We have. Even if I remember correctly, there are five lanterns," Yixiong replied steadfastly, "they're all still in the shed."

"I know we have that thing," Shanquan said, "but will it still work? I don't think we have kerosene."

"It seems that from the five lamps we have, two of them still contain kerosene. Not much, but I think the lights can still be on for about three or four hours," Yixiong said.

"Why didn't Xiongge say that earlier? I mean, before we go down the first time?" Xinxiu joined in on the conversation.

"Sorry. I completely forgot about that. After all, no one mentioned the matter earlier," said Yixiong.

"Okay. Then don't waste any more time," Shanquan said. He patted Yixiong on the shoulder. "Now, you first come to the surface. Go to the shedroom. Check if it's true that we still have kerosene."

Yixiong instantly moved to the corner they had come from. He tapped on the iron rod to signal the man standing guard at the edge of the hole above. A moment later, the rope was stretched down. Yixiong promptly rose to the ground to look for the lamp.

While waiting for Yixiong to return, they sat and chatted on the stone bench in the basement.

"What are our plans this morning?" Xinxiu turned to Shanquan.

"After seeing what's behind that door, we go back into the house." Shanquan said.

"What about Dafeisi Tower? Shall we go there?" Xinxiu asked again.

"Let's see if this morning there are still people watching our house? If there is nothing suspicious, we will continue with the original plan. If there is something suspicious around our house, I think we should come up with other plans. But what is clear, after going upstairs, we rest first, at least for two or three hours." Shanquan tried to stay calm.

"Aren't we going to flee to another place?" Yingyue said at a slow tempo.

The girl's words reminded Shanquan again of the plan he had outlined when they realized certain people were watching their house.

"Yeah, we'll talk about that later. What is clear, after the sun rises, we'll first check the situation around the house."

Yingyue then stood up. She walked around the room. The girl flicked the flashlight at the basement wall. Finally, she stood in front of the door on the east side of the wall that had been opened. She stood and stared at the pitch-black passage beyond the door. Suddenly she shrieked. The girl's scream was loud. Shanquan and Xinxiu ran towards her at once.

"What is it?" Shanquan grabbed Yingyue's hand.

Yingyue was silent.

Shanquan could hear the girl's breathing irregularly. He patted the girl's back gently. "Calm yourself. Inhale and exhale slowly."

Yingyue did as Shanquan said. It was only about seven or eight seconds later that she opened her mouth. "In that passage, there's a flash of light!" Yingyue pointed towards the dark passage that had opened wide.