The story revolves around a high school student named Mahiru Shirota, who likes simple things and dislikes difficult things. One day, he picks up a stray black cat he finds in the middle of the road and gives him the name Kuro. From this moment on, a contract between the servant-vampire Kuro, called "Sleepy Ash," and Mahiru is formed, and Mahiru is pulled into a war between the seven deadly servamp and their eighth sibling Tsubaki.

(Source: Servamp Wikia, edited)