In the city of Kashinokidai, where humans coexist with other beings, one individual stands out even among this diversity. Transfer student Luna Ishikawa, a vampire with a cool and mysterious aura, captivates her classmates and gains instant popularity.

Tatsuta Ootori, an otherwise unremarkable boy, believes that Ishikawa is far beyond his reach. However, when the two are paired for cleaning duty, Ootori discovers that beneath Luna's composed exterior lies an ironic secret. She cannot properly suck blood, forcing her to eat snacks to hide her weakness—but no amount ever seems to satisfy her.

Determined to help Luna master the very skill that defines her kind, Tatsuta offers himself as her practice partner. Through trial, error, and multiple bandages, their unassuming high school days take on a peculiar warmth—one where Luna no longer needs to act flawlessly and can simply be her natural, adorably awkward self.