Identical twins, Yui and Seiren, are sent to Japan to live in the Sakamaki home while their priest father, Seiji, is sent overseas for work. They soon come to realize that the purple they are to house with are not human but vampires. The girls must deal with the sadistic ways of the six blood thirsting vampire brothers as they decide who is to become the 'sacrificial bride' and rule alongside one of the the Sakamaki sons as the vampire King and queen.