Volume 1: In the 1920's, Inaho resurrects a vampire named Mosquiton with her blood. He awakens and becomes her slave. Now, Inaho is after the O-Part, which will grant her immortality. However, a bunch of supernatural monsters are out to stop them from achieving their goal.
Volumes 2-4: Catholic schoolgirl Inaho discovers that a vampire, Mosquiton, is feeding off of her classmates. So she stakes him, but he is revived after her blood comes in contact with the his remains. Mosquiton becomes her slave and also a history teacher. Together, along with Yuuki and Honou, the unlikely duo have many escapades and adventures. One of Inaho's main goals is to find the mythical O-Part to make some money!