The story is set at the blood donation club in Kurusu Private High School. There are four girls who are fascinated by the pleasure of having their blood drawn – Maki (Erika Karata), Jinko (Ichika Osaki), Nami (Mikoto Hibi), and Kaoru (Nazuki Amano). One day, Maki meets Mai (Nina Makino), a beautiful girl dressed in black, in the blood donation room. Mai fainted after her rampage against the nurses, and Maki unintentionally carries her into the blood donation club room. Mai then reveals a shocking fact – She is a dropout vampire who could not attack humans! Struck by Mai's fragile expression, Maki and other members decide to feed her with their own blood instead of donating blood…