A new semester begins at Hyakki Academy, a school where youkai from across Japan gather to study. The story focuses on two first-year students who are already making names for themselves as troublemakers: Mamekichi Maizuka, a mischievous mame-danuki (racoon dog spirit), and Tamao Akisame, a stubborn nekomata (forked-tail cat spirit). On their first day, the two are running late and quickly bond over their shared reputation for causing chaos, becoming fast friends despite being placed in different classes.

The narrative unfolds at Hyakki Academy one year before the events of the main series, A Terrified Teacher at Ghoul School. The school is a lively, chaotic environment populated entirely by supernatural creatures, where rumors of a delinquent teacher who can cleave buildings in half hint at the strange faculty members the new students will encounter. The story is structured episodically, with short chapters that act as a collection of interconnected snapshots rather than a single continuous plot. These glimpses explore the daily lives and developing relationships of the first-year students, providing background and context for moments hinted at in the parent series.

Central to the story is the dynamic between Mamekichi, the carefree trickster, and Tamao, who is more obstinate. Through these shorter vignettes, the manga explores how Tamao develops a crush on a classmate named Kuniko Utagawa and how he eventually becomes best friends with a top student named Rensuke Nyuudou, a relationship that initially creates some romantic rivalry. Another key storyline involves the two protagonists discovering that a classmate named Izuna Hatanaka is actually a kamaitachi (a sickle-wielding weasel youkai) with a past as a former delinquent. The faculty also play significant roles, including Rintarou Miki, the homeroom teacher for Mamekichi’s class, who establishes a playful rapport with Izuna, and the school doctor, whose unsettling physical examinations are conducted using the many eyes scattered across his body.

The manga is notable for its lighthearted humor, which often breaks the fourth wall. Characters directly interact with the author, Mai Tanaka, in a meta twist that adds a layer of self-awareness to the comedy. While primarily aimed at younger audiences with its cute animal forms and comedic antics, the series enriches the world of the original manga by showing the origins of beloved characters and their friendships before the arrival of the human teacher, Haruaki Abe.