Kou Yamori is a middle school student who struggles with grasping the complex concept of love. Plagued with insomnia due to his idleness, Kou begins roaming the lonesome streets at night.

One night, Kou encounters a bizarre girl named Nazuna Nanakusa who believes that people stay awake during the night because they are dissatisfied with how they spent their day and cannot rest until they release their inhibitions. Nazuna offers to help Kou with his sleep issues and invites him over to her place, where she convinces him to share a futon with her. Feeling uncomfortable, Kou only pretends to doze off—which is when Nazuna suddenly bites his neck, revealing herself to be a vampire!

While Kou thinks the bite will turn him into a vampire, the specifics of transforming are not that simple. In order to change, he must be bitten by someone he truly loves. Ready to let go of his dreary mortal life, Kou decides on a new goal: he will fall in love with Nazuna and become a vampire himself.

火风绀（江口拓也 配音）是一个平凡的少年，某一天，绀竟然被召唤到了被称为“米拉”的异世界之中。刚刚来到米拉，绀就发现了被敌方袭击而几乎全军覆没的爱卡尔拉特公主（三上枝织 配音）一行人，此刻，他们正遭到来自于邪恶教团的恐怖组织“因克古尼特”的攻击。在莫名其妙之中，绀打败了队长艾乐库（神谷浩史 配音），解救了公主。作为报酬，公主将带领绀到达都城寻找回到原来世界的方法。
忠心耿耿的骑士森格伦（中井和哉 配音），能文能武的侍女玛丽安戴尔（福山润 配音），可爱的宠物佩特（细谷佳正 配音），在这些同伴的陪伴下，绀踏上了前往都城的旅程。没想到，一路上危险如影随形，敌人不断骚扰，在这样恶劣的情况下，他们能够顺利到达终点吗？

木之幡米拉（高柳知叶 配音）曾经和一个男孩许下了“寻找小行星”的约定，随着时间的而流失，虽然米拉和这个男孩早已经没有了任何的联系，但这个约定却依然被铭记在米拉的心间。
为了完成约定，升上高中的米拉加入了学校的天文社，哪知道为了节省社团经费，天文社竟然于今年同地质社合并，变成了地学社。个性老实，沉默寡言，甚至有些害羞的真中苍（山口爱 配音）、虽然身为学姐，但却异常柔弱的猪濑舞（指出球亚 配音）、常常因为过于认真的性格而被别人误以为在生气的樱井美景（东山奈央 配音）、性格大大咧咧，总是活在自己的世界里的森野真理（上坂堇 配音），对于天空的热爱将这些个性迥异的女孩联结到了一起。