Natsume's Book of Friends Season 5 Episode 10 Natsume Yujin-cho Go

While on the run from a fearsome youkai, Natsume accidently sits on a tiny mushroom youkai. The mushroom youkai is incensed, as it has a meeting with a 'noble person' later in that day. It insists on Natsume helping it prepare for its meeting with this 'noble person', and Natsume finds himself drawn into the strange story of its past...