The Hakata ward of Fukuoka is a hub for various individuals operating in its criminal underworld, including assassins, detectives, informants, and professional avengers. Among them, a legendary figure known as the Niwaka Samurai, an "assassin of assassins," has gained notoriety. Private detective Banba Zenji navigates this dangerous environment, investigating cases for a police friend and playing baseball in his free time. His life takes an unexpected turn when he becomes a target of a powerful crime syndicate and encounters Lin Xianming, a young cross-dresser.
