Takashi Natsume, the timid expert on youkai and holder of the Book of Friends, keeps moving forward on his path to self-discovery and acceptance, aided by companions both familiar and fresh. His most crucial ally remains his gluttonous, sake-loving guardian, the arrogant yet fiercely protective wolf spirit Madara—who goes by Nyanko-sensei when disguised as a harmless, chubby cat.
When Natsume is briefly separated from Nyanko-sensei, he is ambushed and taken captive by a strange group of masked, monkey-like youkai, who drag him into their forest as they frantically hunt for the Book of Friends. Realizing his "servant" has been snatched away from under his watch, Nyanko-sensei rallies Natsume's youkai friends and organizes a rescue mission. But the monkey spirits' forest is filled with dangerous foes, including the Matoba Clan, Natsume's longtime adversary.
Spanning from the Matoba's formidable stronghold to Natsume's own childhood home, Natsume Yuujinchou Shi is a sweeping yet familiar return to a world of peril and camaraderie, where Natsume will finally face the ghosts of his own past.