In order to make him a spy for the government, master swordsman Sakakibara Kazue is wrongfully ordered to commit ritual suicide for overlooking the smuggling of illegal goods. Before his 'Seppuku' can be performed, he is ordered to go undercover with a team of other 'dead' prisoners on a mission to find and destroy a cannon factory being used by the Owari and Takamatsu Clans. As they try to usurp power and gain the position of Shogun for one of their own.