A samurai named Danno Shōzaburō was rumored to be involved in a sword attack against an old friend at his clan’s castle. In order to atone for the incident, he’s given an unusual assignment by the chief retainer.

7 years earlier, Toda Shūkoku was arrested for having an affair with a feudal lord’s concubine and murdering someone who uncovered his infidelity. Because he was working on an important genealogy project for the domain, he was allowed to live with his family for 10 years, after which he would be expected to commit seppuku (ritual suicide). With only 3 years left, Shōzaburō is ordered to move into Shūkoku’s house in order to keep an eye on him. If the man attempts to escape, Shōzaburō is to kill him along with his entire family. However, one day, Shūkoku lets Shōzaburō in on a shocking secret about the feudal domain’s past.