A ninja raised to kill sent to a normal school to eat noodles and figure out what living actually means. Kabamaru keeps trying to solve every problem, bullies, crushes, school festivals, like they're assassination contracts, and watching him fail at being a person is the whole point. The show knows the joke never gets old: a lethal weapon loose in Tokyo, genuinely confused why a girl won't date someone who can kill with a grain of rice.

Kabamaru has grown up under Saizou, his grandfather and his teacher in the Iga ninja arts, a notoriously harsh master. When Saizou dies, an elderly woman steps forward saying he wrote to her and asked her to look after the boy. Kabamaru goes with her to Tokyo, eager to stuff himself with noodle dishes like yakisoba, ramen and chow mein and to start attending an ordinary school. That school, however, proves to have plenty of odd habits of its own. The mix is comedy, adventure and romance.