This was a one-meter-long cave. If not for the undercurrent surging out, Lin Yan wouldn't have discovered it at all.
The dark water and the deep cave placed together made Lin Yan instinctively panic, as if it was the entrance to hell.
Dispelling the instinct in his heart, Lin Yan opened his palm and lit up a ball of Spirit-Snatching Demonic Flame. As a light source, he crawled into the cave.
The cave entrance was not small, enough for a person to pass through. The walls of the cave had long become extremely smooth after being washed back and forth by the undercurrent.
Furthermore, the cave wall should be vertical, like a deep well at the bottom of the lake, leading to an unknown deeper abyss.
However, as Lin Yan swam deeper, the interior of the cave shrank and became narrower.
After descending less than 20 to 30 meters, it was so narrow that no one could pass.