Chiyuki Matsuoka, 17, has a serious heart condition. Toya, 18, is a vampire who hates blood and refuses to enter into the traditional partnership with a human, whose blood would keep them both alive for a thousand years. Chiyuki has formed a bond with Toya and wants to live her life to the fullest, but she doesn't realize that Toya refuses to enter into the full partnership with her, being unwilling to doom her to live one thousand years.