Natsume's Book of Friends (2008)

S5E7 Distant Festival Lights

Natsume and his friends travel to a remote hot spring to assist with some renovations. Upon arrival, Natsume encounters an old acquaintance of Tanuma's, but soon finds himself entangled in local youkai issues. It turns out Tanuma's friend is actually a youkai, and she warns Natsume of dire consequences if he discloses her true identity.