Kou Yamori, a typical middle school student, finds the idea of love puzzling and eventually quits attending school as he questions the point of conforming to societal norms. His newfound idle life leads to insomnia, and he starts wandering the empty streets at night.
During one of his nocturnal outings, Kou meets Nazuna Nanakusa, an odd girl who suggests that people who roam at night are simply trying to cope with dissatisfaction from their daytime activities. Nazuna claims she can cure Kou’s sleeplessness and invites him to her home. There, she persuades him to lie down with her on a futon. Despite feeling uneasy, Kou feigns sleep, only to be shocked when Nazuna bites his neck, revealing her true identity as a vampire!
Kou initially believes this bite will transform him into a vampire, but the process turns out to be more complicated. He must be bitten by someone he genuinely loves to undergo the transformation. Determined to escape his mundane human existence, Kou sets a new objective: to fall in love with Nazuna and turn into a vampire.
[Adapted from MAL]