In "Natsume's Book of Friends Season 4," Takashi Natsume, a reserved but capable youkai handler who holds the Book of Friends, continues his journey of self-discovery and acceptance with the support of both familiar and new allies. His closest companion remains Madara, a self-proclaimed wolf spirit who is both greedy for food and sake and fiercely protective of Natsume, though he often passes himself off as a harmless, plump cat called Nyanko-sensei.
One day, while briefly separated from Nyanko-sensei, Natsume is captured by a mysterious group of masked, monkey-like youkai who are desperately searching for the Book of Friends. When Nyanko-sensei learns of Natsume's capture, he quickly gathers Natsume's youkai friends to launch a rescue effort. However, the monkey spirits' forest is filled with dangers, including run-ins with the notorious Matoba Clan, Natsume's long-standing rivals.
From the Matoba Clan's imposing fortress to Natsume's childhood home, Natsume Yuujinchou Shi revisits a world full of peril and camaraderie, leading Natsume to confront the lingering shadows of his past.