In Fukuoka's seedy underworld, crime runs rampant. The Hakata ward is especially hard-hit, being a gathering place for top-class assassins, private eyes, information-mongers and "professional revenge-seekers." Perhaps the most legendary among them is the Niwaka Samurai, notorious for being an "assassin of assassins." In the midst of all this, private detective Banba Zenji appears to be the eye of the storm, calmly and cheerfully investigating cases for his police officer friend and playing baseball in his spare time. But when he himself becomes the target of a powerful crime syndicate and has a run-in with a young cross-dresser named Lin Xianming, life in Hakata may never be the same again.