Komori Yui lives her life together with six brothers (by father's side). However, it is not the common daily life! In fact is quite a radical life, she is oppressed by them, and blood is demanded, as they are all vampires!
The story begins in 1629 Shizuoka during Tokugawa Tadanaga's rule. The daimyo staged a tournament where the participants fought with real steel Japanese swords rather than bokken, against his vassals' strong objection. The story revolves around the first match between the one-armed swordsman Fujiki Gennosuke and the blind samurai Irako Seigen and deals with the circumstances that led the two to participate in Tokugawa's tournament.