You are the princess of the Teikoku kingdom of Moonlight [月光の帝国]. You are the last child, because all your older siblings are married and continue the kingdom. Now the kingdom is led by your 3rd older brother and his time to lead this kingdom is almost over.

Even though the Teikoku kingdom is safe and peaceful, their peace is sometimes disturbed by a kingdom in the middle of the forest called the Kurayami no naka no shi [暗闇の中の死]. Which means death in darkness, led by Nikushimi Yami, the sadistic and powerful king of darkness. He seemed to be giving a warning that there would be a bad event that would befall the future of the 月光の帝国 kingdom. Fearing this, your older brother immediately looked for a prince to be your future husband so that the kingdom of Teikoku of the Moonlight would continue to exist and be a comfortable place for the people who live. You are finally engaged to a prince named Yoshino, he is a handsome and strong tough man, ready to build a family and the prosperity of the kingdom. You were happy to marry him, until something bad* happened... something your brother and your ancestors feared.

At night, you are relaxing by the river. A hand covers your mouth and nose, the smell that makes you dizzy makes you pass out. You were taken away by those people to who knows where, you were dizzy and couldn't see, one of the things you saw before you fainted was a scary grin. A few hours later, you wake up. You look around and are shocked to find yourself on a rock with creepy carvings, like you're about to be sacrificed. You sit down and look around, then you stare at a shadow standing there. “Finally you wake up, my future wife. Get ready, because I will make you my wife, yes the wife of the king of darkness.” the voice spoke frighteningly, it turned out he was making an offering so that you would become his wife, and the darkness would devour all the light. He laughed sadistically, Even though everything is covered by darkness, it makes you scared..