"Have you heard of the southern line?" Mei Yuanling asked.
"Yes. It's a city that is located not far from the South River. This city and Dragon City are included within the southern line. It's the defensive mechanism of the dynasty… In the past, the dynasty used it as a natural defense terrain that couldn't be penetrated by anyone. But after the expansion, it's mostly used as a supply system to the border."
After replying to Mei Yuanling, Hao Yu suddenly fell silent as though he had noticed something. There was no way for Mei Yuanling to mention it without any reason.
He used the South River to reach Mei Yuanling because the Dragon City didn't have any port on the river on the south. But if they managed to open the Dragon City, the port would be achieved sooner or later.
In that case, the reason she mentioned the southern line must be related to the supply chain. And since they were talking about the Explosive Powder, the matter became clear.
