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…

Energy-conservative high school student Houtarou Oreki ends up with more than he bargained for when he signs up for the Classics Club at his sister's behest—especially when he realizes how deep-rooted the club's history really is. Begrudgingly, Oreki is dragged into an investigation concerning the 45-year-old mystery that surrounds the club room. Accompanied by his fellow club members, the knowledgeable Satoshi Fukube, the stern but benign Mayaka Ibara, and the ever-curious Eru Chitanda, Oreki must combat deadlines and lack of information with resourcefulness and hidden talent, in order to not only find the truth buried beneath the dust of works created years before them, but of other small side cases as well.

Natsume Mochizuki works as a teen model in Tokyo, but she learns that she has to move to her father's hometown of Ukigumo. She is in a desperate situation because she can't do the things she wants to do in Ukigumo. One day, she meets Koichiro Hasegawa. He is the successor of the Hasegawa family. His family is wealthy and is respected in the area. Natsume Mochizuki and Koichiro Hasegawa become attracted to each other, but something changes their fate.