The Sagemiya family is cursed because members of the same bloodline feel sexually aroused in the presence of another person of the same bloodline. Sagemiya Misaki and her elder twin, Shun, are both repulsed by this and have vowed to fight the blood call. Shun, on the other hand, loses his cool and seeks help from their eldest sister, Kagu. Misaki, too, loses her willpower after learning the truth and seeks out Shun.