Seirin Academy, a famous academy with a long history, is one of the leading places of education for young ladies far and wide. It is also place where Tsujiura Mio just transferred to, and somewhat... strange. Seirin Academy has a number of taboos, one of which is getting involved with the upperclassman Nekonome Yuuka, someone Mio can't help but be drawn towards. And when Mio does start interacting with Yuuka, she begins getting caught up in all sorts of inexplicable occurrences, after all, Nekonome Yuuka is not alive.

So, who, or what, is Nekonome Yuuka? And what secrets are hidden away in the hallways the dainty young ladies of the Academy walk down every day?