Onohara Mikage is sold into slavery to settle her parents' debts and is handed over to a vampire named Claude for rigorous "training." Forced to endure degrading sexual abuse and energy drainage, Mikage is groomed to become a "Princess" in a vampire town. As she is subjected to the sadistic whims of Claude and his companion Himeno, she realizes she has entered a nightmare where her body is used as a mere tool for vampire sustenance.
Mikage is subjected to further brutal torment as Claude uses her as a sacrifice to complete his ascension into a full vampire. Through a combination of physical abuse and a mind-altering wine, Mikage's spirit breaks, leading her to succumb to a twisted state of pleasure. Despite her desperate pleas for freedom once the process is complete, Claude coldly denies her, ensuring her continued captivity.