Juusan-nin no Shikaku.

The head of the Mamiya clan committed suicide in protest against the feudal lord, Matsudaira. Matsudaira is a tyrant whose brother has appointed him to join the shogunate. The elderly Doi approaches Shimada Shinzaemon to carry out an assassination in hope of avoiding the war he feels is to come should Matsudaira get even more power. Though he initially refuses, Shimada decides to gather reliable people to assist him. But, on that fateful morning..