Hi no Tsuki

End of Edo period.
Main character travels with a master of the sword searching for Kanzaki who killed protagonist's adopted father. In the middle of the trip they get caught up in a case in a small port town. In the mids of investigation the name of Kanzaki shows up, but in a new context - linked to gods, opus and castle lord. The hour of revenge draws near.

[From vndbreview]