"Dang..."
The sound was very faint, and with the passage itself having a sound transmission and amplification effect, Ling Mo initially judged that the sound source was still relatively far from them...
As the two of them sped up their crawling, that faint "dang dang" sound rang twice more intermittently, sounding as if someone was tapping on the pipe overhead.
"If someone is indeed knocking, it must be Xia Na..." Ling Mo thought to himself.
The two of them tacitly kept silent, afraid to drown out the faint sound.
This passage maze actually contained quite a few crisscrossing forks, some leading upward, others downward. If they heard wrong, they might be led into a wrong path and completely miss the sound source.
Moreover, judging from Li Yalin's decisive attitude, the direction from which the sound came was clearly in line with Xia Na's direction, hence Ling Mo's judgment.
"Faster, faster..."
Ling Mo's hands kept grabbing forward as he growled anxiously in his heart.
