This is a world where vampires and humans live together. Recently, there have been frequent cases of vampires attacking humans, which has caused panic among people. Everyone lives in panic. Caisha (voiced by Yui Ishikawa) is an ordinary female graduate student at a university. One day, her classmate invited Caisha to play, and the two of them played until midnight. At this time, the classmate revealed his true face. It turned out that he was the culprit of the vampire serial murder case, and Caisha was his next target. Just when Caisha's life was hanging by a thread, a man named Anzai Yuki (voiced by Yoshitsugu Matsuoka) appeared in front of the two and became Caisha's savior. It turned out that Anzai was an investigator of Class F of the Fifth Public Security Section of the Metropolitan Police Department. Although he is also a vampire, he is a vampire hunter. Anzai not only saved Caisha, but also took away her first kiss, making Caisha fall in love.