Bitten by a vampire at a club, nineteen-year-old En barely survived. Taken under the wing of Ichii — a member of the health and welfare division of the vampire rights organization known as FANGS — En learns he's to be taught about this new "world" he must survive in.

In order to control the urge to suck blood and attack innocents, FANGS established a "pairing system", where two vampires support one another with regular meals. As a young, virginal vampire, En is highly sought after by many senior vamps. That is, until he declares his intention to pair with his guardian, Ichii...