A kid discovers he's the literal last heir of a ninja clan and has to learn how to be a shinobi before his enemies kill him. That's not setup, that's the whole show, executed straight, no irony. The Iga versus Koga conflict is real, the stakes are immediate, and Ittoki doesn't have time to be uncertain about any of it. This is the rare action show that trusts its premise completely and builds everything around making you believe a teenager can actually survive what's coming for him.

Ittoki Sakuraba cannot understand why his mother, his uncle and his childhood friend Kousetsu guard him so closely. The reason becomes clear when a second-year student, Satomi Tsubaki, asks him on a date that turns out to be a trap: she means to kill him, and she has help. His uncle and Kousetsu rescue him dressed as ninja. Afterward his mother tells him the truth: he is the 19th heir of the Iga ninja clan, and the rival Koga clan wants him dead. To defend himself and his village, Ittoki enrolls at Kokuten Ninja Academy, a high school that trains shinobi, where modern ninja rely on advanced suits and gear. Joining classmates from other ninja villages, he takes on the Koga, hoping to end the feud for good.