A royal guard infiltrates the slave city of Ishtal to rescue Princess Jill, only to be betrayed and sold into sexual slavery herself. She discovers that Jill and a priestess named Lunalie have also been captured and are being subjected to brutal abuse and aphrodisiacs by a sinister cult. Despite the relentless torture and humiliation, the guard's desperate desire to protect her companions leads her to seek a forbidden power, even if it means selling her soul to a demon.