A shikakenin was an under-the-cover trade that undertook killing in Edo. Hanemon of Otowa, an agency that introduced laborers and maids, was also one of these. Katsugoro Iseya was a timber dealer who had come in as a client. His target was the constructions magistrate Hanno, and the Tatsumiya who sipped on the benefits. Hanemon who had a stong code towards killing, where he would only kill those who do no good to be in the world, accepts this request. Baian Fujieda, a needle doctor would carry out the killing. However, the professional killer Baian fails to bring down Tatsumiya. Hanemon then looks to another shikakenin, the ronin Sanai Nishimura for the role. Although Sanai's ability with the sword is good, he lives poorly in a tenement, and accepts this commission on the condition that it is kept a secret from his wife and child. Here, they close in on Hanno and Tatsumiya again...

The drama depicts in the late Edo period in Nagasaki, Hiramatsu takes up Nagasaki bugyō`s head post. He likes alcohol and women. Furthermore He is always willing to accept a bribe from villains so they consider it is easy to manipulate him. But he is just pretending to be idiot and he kills villains who escape justice despite their crimes.