Lou Lan’s Idea

Autumn Water channeled elemental energy into the bronze lantern she was holding and a wispy, bean sized flame lit up. The flame shot out a green light ray that shone onto the ground.

The green ray was very weak, but the illuminated spot on the ground quickly became transparent and the maze-like sewerage system appeared before their eyes.

The rest were startled as it was the first time they’d seen something like this.

Autumn Water’s lantern, "element-chasing lantern", was a weapon used to track enemies. Elemental energy would be needed to track sand puppets who’d fled this way since there would be traces left behind, unconcealable before the element-chasing lantern.

The green light followed the elemental energy traces and moved rapidly.

Where the light passed the ground, it returned to normal. When the light shone on the thick, solid ground it became crystal clear and so did the underground structure.