"In the twentieth century, there was a massive conflict between people and monsters, and Monsters won the struggle. With the onset of the new century, memories of those times completely disappeared from the minds of people." Monsters rule out of the shadows, while people continue their lives with the likeness of normality, all the time with secret fear. Some are trying to earn the favor of monsters, offering child sacrifices. Most closes their eyes and pretend that it does not exist. But there are several, Melos Warriors, who continue to fight with monsters and are looking for a melody of oblivion, a mysterious girl, which, as they say, is the key to salvation. The young serine of the bed wakes up like a Melo Warrior, and begins his journey in search of the melody of oblivion.