Jack followed the directions he had memorized. Grace and Oswald followed him. When Grace kept on complaining about the rats, Jack informed Grace that the rats were the key, they needed to follow them. He then gave her a simple explanation about the nature of this forest, about how it was separated into different cells that trapped those who traveled inside. Only when one passed through a node that one could travel in between these cells.
When Jack brought her passing through her first node. She didn't feel anything. Her mana sense was still at its very beginning stage. She had to close her eyes and concentrate before she could feel an inkling that something was unusual there.
They went through three nodes before arriving at the cell where Jack last saw Jet. They started searching around. As long as Jet was still within this cell, they would stumble into him sooner or later.
After wandering for a while, they heard something. "Sounds like fighting," Grace said.