It begins with a boy in high school getting an invitation from a girl to meet up. when he gets there he finds that shes a vampire who wants some of his life energy. So the boy comes up with a compromise she can have his semen life energy but she has to get it out.

Kanzaki's a bit worried that Mari will leave him for someone else. However, she insists she won't and tries out a few new ways to extract Kanzaki's semen.