Yofukashi no Uta
Call of the Night
Kou Yamori is a middle school student who has trouble understanding what love is. He disliked school and stopped going. Due to his laziness, he developed insomnia.
One night, he meets a strange girl called Nazuna Nanakusa. She believes people can't rest until they free themselves from stress. She invites him to her place and they share a futon. Then, she bites his neck and reveals herself to be a vampire. Kou thinks he will become a vampire too, if he finds someone he truly loves and gets bitten by them. He now has a goal: to fall in love with Nazuna and become a vampire.