Shiragami Youko is a half-vampire. Her father is a vampire while her mother is a human. Youko is going to a human school under a condition that the fact that she is a vampire must be kept secret. However her secret was exposed to Kuromine Asahi, who intended to confess his love to her and witnessed Youko unfolding her wings in an empty classroom.

As a vampire Youko possesses such characteristics as wings and long canines. She can easily hide her wings but can't do anything about her canines, which is why she avoids showing her teeth at school as much as possible. Youko is also weak to sunlight, but instead of turning into ashes she just gets tanned extremely fast.