In the dark alleys of the world of shadows, the demon Harkow makes the bold decision to incarnate in the human world. His fateful encounter with Grimson Xenolite, a seemingly ordinary high school student, triggers a series of supernatural events. As Grimson juggles his everyday life as a high schooler, along with family and friendships, he gradually discovers the mysterious powers within him. Amid demonic forces and benevolent angels, Grimson must navigate a world where the boundaries between the supernatural and reality blur, unveiling secrets buried for centuries.