He Dao Ba didn' t say anything and quickly found another copper nail in the pile of arrows.
Could it be that this copper nail had some mysterious mechanism?
"I understand." He Sheng took the copper nail and looked at it carefully. He seemed to have come to a sudden realization." There are some special patterns on the back of the copper nail. I guess there must be a door opening device on the back of the door."
He Dao Ba nodded in approval. It seemed that he really appreciated his observation.
So He Sheng held the two copper nails and floated to the top of the door again.
He carefully embedded the copper nail into the original gap. When the second copper nail was also embedded into the original position,we clearly heard a "click" from the door.
That voice was very clear in the empty t
