As a child, Okin the one-armed one-eyed swordswoman was disfigured by Lord Daizen-dayu, who was after her family's most treasured possession, the famed Drenched Swallow sword. As an adult, she has become a skilled swordswoman and lives a carefree life with her adopted family. One day, Okin saves a girl from a group of yakuza, and in doing so, gets involved in a grand conspiracy involving religious leaders, government officials, the yakuza and Lord Daizen-dayu, the man who killed her father and mutilated her body...

Enfant, O'Kin est gravement blessée et défigurée par le Seigneur Daizen-dayu qui cherche à mettre la main sur un sabre légendaire détenu par la famille de la jeune file. Devenue adulte et épéiste de talent, O'Kin va recroiser la route de Daizen-dayu...