故事发生在德川幕府统治下的江户时代。在设定中,胸部的大小成为决定一切的标准,较大的胸部成为国王,较小的胸部成为战败的敌人。因此,拥有可以放大乳房的祖传秘书的魔乳一族,真正将生死掌握在他们手中。
这支部队由中岛中将创建,旨在对抗现代大国的情报战,但零机构目前的任务是应对隐藏在东京的吸血鬼事件。被指派担任这项工作的人是最强的人类前田吉野,这个国家排名最高的吸血鬼,也是机制的新人黑井秀夫。他的智慧超乎寻常,从江户时代起就一直存在。他也是一个疯狂的科学家,喜欢他日渐衰老的大脑竹内。以上是零机构执行部队的成员。吸血鬼的数量越来越多,秘密行动的阴影,神秘的人造血液的存在,以及这些事件的冷眼观察者是S级吸血鬼Dave Roth,尽管他已经300多岁了,但他的外表与儿童相似。零机制今天,穿梭于大正的浪漫之夜。
Tanaka Tetsuro is excited at getting a full scholarship at a new high school, far away from his family. What he does not know is that he will be the only boy in an all girl school, and that there is a girl head-over-heels in love with him, waiting for his arrival. But his special friendship with the very cute and dynamic Asuka also causes him to get into a lot of trouble with the powerful student council leadership, as they are at open war with Asuka and her five friends, a group of super amazon warriors called the Koi Koi Seven.