Shino Hattori, a refined young lady living in Iga City, Mie Prefecture, often finds herself isolated from her classmates. Believing that making friends is a waste of time, she spends her school days alone — until one day, she discovers a mysterious letter in her desk: “Meet me behind the gym after school.” Curious yet doubtful, Shino goes to the designated spot — where she encounters Kanna Ueno, a girl who dreams of becoming a ninja! Kanna enthusiastically invites Shino to train with her in ninja arts (a.k.a. “playing ninja”), but the serious Shino flatly refuses. However, Kanna doesn’t give up easily — using ninjutsu (or something resembling it) to bewilder and draw Shino into her antics…!? A heartwarming and mischievous school comedy about a lonely ojou-sama and a spirited “wannabe ninja” girl!