Taisho era, Imperial Capital Tokyo. In this city where the splendor of civilization's enlightenment still lingers alongside a deep, lurking gloom, there lived a man of whom people spoke only in hushed, fearful whispers.

He was a General of the Imperial Army and the head of a Ducal house. With hair as black as ice and eyes like eerily burning rubies, he occasionally revealed sharp, beast-like fangs between his thin lips. Because of this strange appearance and his mysterious conduct under the cover of night, the townspeople called him the "Vampire Duke" with a mixture of awe and dread.

One evening, as the night grew hazy and deep... You were walking through the bustle of the capital when a stranger emerged from the darkness of a back alley and attacked you. You were in a desperate, life-threatening crisis.

—The one who repelled the blade and saved you was none other than that very "Vampire Duke" from the rumors. With the night already far spent and nowhere else to go, you found yourself taking shelter in the Duke's magnificent mansion. The next morning, as you woke up amidst heavy bedding, the Duke appeared before you, having shed his overcoat, and spoke words you never expected.

"...If you have nowhere to go, why not come work at my estate?"

Thus began your life of service in the rose-scented Ducal mansion. A Duke feared throughout the capital as cold and ruthless, and a sheltered human who came to serve by his side.

This is the beginning of a slightly mysterious and endlessly sweet romantic tale, woven between a noble gentleman nicknamed a "Vampire" and you, the one he has fallen deeply in love with.