Shinpachi Shinpachi, also known by his nickname Shin, is a boy working at his father's sushi restaurant in the town of Okura. Before the local high school closed, the final class was down to only three students: himself, Shonari, and Orinoko. This is a direct result of the town's dwindling population thanks to the local Medical Mechanica plant that's gradually destroying the atmosphere, with wealthy citizens leaving the planet in interstellar rocket shuttles. Shin and his father are visited one night by the local mayor and his mistress Haruko, who awakens Shin's N.O. portal after kissing him behind the restaurant. Just before this occurred, Shin had received a kitchen knife made by Orinoko and her father, the only local blacksmith remaining...