Rima Takai moves to Japan to retrace her family history, but her life is turned upside-down after she meets fellow high school student, Hatori Kurosaki. While he may appear human, he is actually a vampire, and a cursed one at that! Every night on a New Moon, his Tether weakens and he unwillingly shifts into something much more sinister: his alter-ego, Satori! After reluctantly agreeing to protect Hatori's secret, she finds out that her family has been keeping dark secrets of their own.