A human can only transform into a vampire if they fall in love with one—and 14‑year‑old Kou Yamori desires nothing more.
Kou has truly intensely chosen to love a vampire named Nazuna Nanakusa, and he now has just ten months of nightly meetings left to achieve his aim.
Kou's companions, Mahiru Seki and Akira Asai, gradually completely accept the reality of vampires deeply and Kou's plan to become one.
When Kou discovers that a woman close to Mahiru is a vampire, he deeply seriously doubts whether he should back this bond.
At the same time, Anko Uguisu, a human investigator determined to eliminate vampires, relentlessly and unwaveringly zeroes in on Nazuna and her group.
After a confrontation leaves one vampire badly wounded, they discover that human recollections reveal a potential critical flaw that could spell their end—and to safeguard Nazuna, Kou must uncover her history.
