When traveling to a castle in Germany to take photos of paranormal activity, Kouhei Morioka meets a young vampire by the name of Hazuki who tries to turn Kouhei into her slave but fails. Despite failing to enslave Kouhei, she is freed from her captivity. Returning to Tokyo, Kouhei is surprised to find that Hazuki is now going to be living with him and continues to insist that he is her slave.