Three men sentenced to death are spared and changed into "shadows executioners�, a group of ruthless ninja working for mysterious high ranking officials. During their investigation on some illegal business, one of them, called "Yazuke the Viper�, finds his abandoned daughter, Ocho, who has now become a mistress of Denzo, a smuggler. After Yazuke's death, Ocho is also recruited as a "shadows executioner�, with the task of completing her father's mission.