Writer Hasegawa Mitsuru has been investigating a case that was rumored to be the work of vampires known as “Biters”. His childhood friend, Annaka Yuusei, a.k.a. Anna, warns him not to stick his head into where it doesn’t belong.
On top of that, he impulsively sleeps with Anna and experiences indescribable pleasure. In addition, there seems to be a secret about Mitsuru that he himself isn’t aware of…?