Yui Hatano, a descendant of the Shiranami clan—a ninja lineage with a history dating back to the Edo period—lives in quiet seclusion deep in the mountains, far removed from modern civilization. As a wandering shrine maiden, she travels across regions, performing arts and dances while secretly gathering intelligence. To protect her sisters and safeguard the secret scroll known as "Kotobuki," she is forced into battle against the rival Kuroha clan. However, captured by powerful enemy ninjas and overwhelmed by superior tactics, she is subjected to brutal torture. Under relentless interrogation for the scroll's location, she endures the stone-embracing punishment, suffering severe leg injuries that cripple her once-agile fighting techniques. With her mobility destroyed, she is then brainwashed through eerie black ninjutsu, her mind twisted into craving the very enemies who enslaved her. Her body and soul succumb to lewd desires, leading her inexorably toward tragedy.