"It's enormous!" the old man said.
"The last time you came, did you find any monsters inside?" I asked again.
"No!" the old man replied, perplexed.
After waiting for a while and nothing appeared from the door, I gathered my courage. With the cavalry captain's cover, I opened the door. It was pitch black inside. I extended my Qi sensing technique downwards and ahead, and indeed saw the aura of some living beings, but they were all very far away. Moreover, I also heard the sound of rushing water coming from below.
"Lao Wang, they might have been driven into the water by you," I patted his shoulder. "Don't be nervous, go get a torch."
"Sir, you take this." Lao Wang handed me his spear and ran into the woods. We had passed a forest that looked like pine trees earlier. Whether they were pine trees or not, I saw a lot of something resembling pine resin on the tree trunks. That substance was flammable and could be used to make torches.
Bingbing and the old man also came over. I asked the old man if there were any oil lamps inside. The old man recalled for a moment and said there seemed to be, but he didn't remember the location. It would require going in and lighting them with a torch.
Before long, Captain Lao Wang returned. He used the inner lining of his clothes, soaked in grease, and wrapped it around my hiking stick. I took out my matchbox and used the last match to light the torch. Lao Wang held it up and entered the pump room.
"Sir, be careful of the steps!" Lao Wang reminded me.
Inside the small house, there was only a downward staircase. Nothing else. Following the stairs, we reached the interior of the dam. After a turn, illuminated by the torch, I saw a large hall. There were indeed several oil lamps on the wall. After Lao Wang lit one, possibly due to oil pipes connecting them, the oil lamps lit up one by one, quickly illuminating the entire hall.
It turned out to be a very modern-looking engine room, with many huge gears meshing together, and some equipment whose principles I couldn't understand.
The sound of flowing water came from beneath these large gears. I peered down through the gaps with the torch. The gears extended down many thick transmission rods, and it was estimated that there were similar gear mechanisms below, but they were all underwater and unclear. On the transmission rods, there were only ladders similar to the external fire escapes of buildings. They looked sturdy, fixed to the rods with rivets, presumably for climbing down for maintenance.
The auras I had seen earlier had already dived underwater, likely water spirits. Bored, they emerged from the water and climbed up the ladders into the pump room, startling Lao Wang and me.
"Did they time travel?" Bingbing exclaimed, "It feels more advanced than a modern dam!"
"That's because you haven't seen a modern dam," I laughed. "Modern dams are all digitally controlled. You press a button, and you can release the flood."
"That's true..." Bingbing nodded.
"Let's start studying, see which mechanism is used to cut off the water flow," I said. Our first task was to dam the river. Once it filled up, then releasing the water would inundate the downstream area.
Everyone split up to search, but after looking for a long time, they couldn't find anything. Could we not directly try to move the gears? Each tooth of these massive gears was larger than my head. They could withstand such strong water flow, so they definitely couldn't be moved easily.
After searching, the four of us returned to our starting point. I peered down through the gaps again: "Could it be that the mechanism is underwater?"
"It's not impossible. I'll go take a look!" Bingbing volunteered.
How could I let her do such dangerous work? Of course, I couldn't do it either. Although I didn't need to breathe and could dive indefinitely, our weight simply couldn't withstand the impact of the water flow. If we went down, we would be washed away.
I asked Bingbing to go out and call the big catfish from downstream!
"...Can it swim up?" Bingbing frowned.
"If it can't swim up, have it transform and walk up!" I said.
"Alright, I'll try," Bingbing went, and quickly returned. "No, it can't transform, nor can it stay out of the water for too long."
I slumped to the ground. What then?
"Brother, why don't you ask those monsters that Brother Wang drove away?" Bingbing suggested.