Nintama Rantarou: Ninjutsu Gakuen to Nazo no Onna - Kore wa Jiken da yo! no Dan

During a routine errand, Rantarou and his companion Fushikizou stumble upon a curious scene: a mysterious woman being pursued by ninjas from Tasogaredoki Castle. As the chase unfolds, they discover that she is, in fact, Hieta Happousai, the cunning leader of the Dokutake Castle ninjas, cleverly disguised to maintain her identity.

This unexpected encounter sparks a series of events that draws the entire Ninjutsu Academy into the fray. With humor and intrigue, the students find themselves navigating a web of secrets and rivalries, showcasing their unique skills and camaraderie in the face of escalating chaos.