The mussel was considered to have done an excellent job as it could dig half a mile of railroad in an hour.
"Mussel, have you been staying in the fifth mountain since the beginning and left before?" Gu Xijiu highly suspected the possibility.
"Yup." The mussel added, "I’m a mussel, I don’t have to go out."
Indeed!
Gu Xijiu smacked her head as she wanted the mussel to dig a path to the upper ground. However, she seemed to have sensed something. She walked further and placed her fingers on the freshly dug wall.
There was something on the wall!
Since it was just soil, she took out a blade and poked it. However, the blade could only penetrate about an inch into the wall and stopped. Something in the wall was restricting the penetration.
The blade could even penetrate an iron wall in a single poke, not to mention the soil. However, there was something stronger than metal behind it!
