As they continued to go deeper into the cave, they found a clean stream.
The stream flowed through the mountain valley they had been walking on. Song Feiyao told them this was the exact stream they were looking for that crossed the ancient village before reaching the Yellow River.
The clear stream water suggested that the stream did not flow on the surface. Otherwise, the surrounding mud and dirt could easily turn it muddy.
The stream water spilled out from the rock strata, then passed by a fault valley blocked by the rocks. The mysterious and ancient village where the Underground Holy Spring was located at the fault valley.
The rock mass on top of the mountain within the fault valley resembled a gigantic umbrella that blocked the sun from view. It covered the entire fault valley. Even if one looked down from the sky, they could not possibly notice the cave down there.