日本犯科帳 隠密奉行 久留米篇

In the Kurume-Arima domain, Lady Okuni and the chief retainer conspire to poison the eldest son of the Arima family in order to install the second son as the next lord of the domain. The suspicious swindlers operating in the shadows are connected to Lady Okuni, and their actions embody the sorrow and hopes of a family that is not allowed to descend to the village. The chief retainer plans to eliminate the Arima family concubine once his plan is successful and become the successor… then a secret agent steps in to stop the assassination.