In Edoropolis, countless mechanical animals live together in harmony. But when Lord Wanko discovers that the shogun's chief advisor, Lord Korn, is scheming to seize control of the government, he knows action is needed to keep the peace. To stop Korn, Wanko establishes the Nyankees—a group of elite ninja led by the courageous Yattarou, who wields the mystical blade Masamasa. With such power, the Nyankees appear unstoppable.
Yet Korn's conspiracies aren't their only concern. Operating in secret from the Pizza Cats restaurant, the Nyankees must conceal their activities while delivering hot plates of pizza and justice.