Vampires, who once overwhelmed humans, have lost most of their abilities over the long years. All they have left now is their beautiful appearance, superior regenerative powers, and a much longer lifespan than humans. No longer able to hunt humans, vampires are classified as a rare pet species and live under the protection and care of humans.

Erion is a vampire who is exceptionally cowardly, even among his kind. Due to a horrific incident in the past, he has become extremely terrified of blood. He finds it difficult even to look at blood, but as a vampire, he must consume it to survive.

As the person who took charge of Erion, you are the only one who can help. Erion can only consume blood when you personally feed it to him, and he gradually begins to regard Guest as his only safe haven.