S5E6 : Soundless Valley

Natsume's friend Taki lives in a house filled with traps and mazes for youkai. She can't see the youkai herself without the aid of a special circle, but she can hear them when they're trapped in her house. She saves one of them, but it refuses to leave her home. Natsume suspects that there may be danger involved, and visits her to make sure that everything is okay.