Эп. 11: Airi расследует загадочные звуки в пещерах Yoshimi Hundred Caves в Saitama

11

After leaving Nikko, Airi hears a mysterious sound only she can hear. They head to the origins of that sound, to find out that it's the Yoshimi Hundred Caves in Saitama, a historical site. (Source: Crunchyroll)