Normal high school girl Irie Yuunagi suddenly has her blood sucked by a strange man one night. Yuunagi wakes up as a vampire and learns that she has been added to the man who bit her, Rin's, family. She begins to learn about the rules of the vampire world from Rin.

Maki-kun goes to look at the results of his high-school entrance exam results and meets a beautiful girl. Could this be a fated encounter? He's thrilled to find out that the same girl, Aikawa Kizuna, not only ends up going to his school, but is in his class. However, he's not so thrilled when he finds out that Aikawa isn't a girl! Not a girl, and not really a guy, kind of both -- and Maki finds himself getting along with popular Aikawa, getting pulled in to his pace!