There are two paths to Fran Fortress, one is to walk on the ground, through Cold Valley, to reach the fortress gates.
The other is to walk underground, along the underground tunnels to pass through the mountain and enter the depths of Fran Fortress.
Night Mouse's suggestion to Fang Zhou is to walk on the ground. Although it is dangerous, the monsters in Cold Valley are predictable, and as long as one is careful, there won't be big issues.
The underground tunnels, however, are different—countless tunnels crisscross more densely than a spider's web, a haphazard rush would definitely lead to getting lost, and even Night Mouse doesn't know how many types of monsters are in those underground mines; the Maggot People encountered earlier were just the most ordinary and common kind.
Fang Zhou was quite agreeable, choosing to heed Night Mouse's advice and travel on the ground.
