Sorey is a human adolescent who grew up among the seraphim, invisible spiritual creatures to humans. Sorey believes in the tradition that "long ago, every human was able to see the seraphim" and aspires to solve the old riddle in order to make the world a place where people and seraphim may coexist together. Sorey goes to the human capital for the first time one day. He is involved in an occurrence in which he takes out a holy sword embedded in a rock and ends up becoming a Shepherd, someone who throws out misfortune from the earth. He begins to understand the importance of his task, and his desire of cooperation between humans and the seraphim grows more intense—and thus, the story begins.