Humans and vampires can't live together. in the world. The ancestors who once tried to do this paid the price, because the greedy nature of vampires forced them to subjugate humans.

In this world, people are their pathetic toys. Those who are lucky enough to charm vampires are called "donors", they give their blood, allowing vampires to feed on themselves, in exchange for a good and comfortable life.

But Sin is not like that. He is a half-breed, and therefore perfectly understands people and their misfortunes in living in the same world with vampires. He was often bullied as a child, but he still grew up to be a good-natured and sweet guy, thanks to his best friend, the vampire prince.

Right now, he's waiting for his friend, sitting on the balcony railing at the private school where vampires and humans coexist, that's how he noticed you with your strong scent.