In the fourth year of the spiritual qi revival, high school senior Li San is caught in a "Black Tide Invasion" during evening study hall. Wielding a black sword from the abyss, he awakens the power to devour souls. To protect his younger sister, he is forced to join an organization of spirit tamers. As the black sword devours the memories of his loved ones and his teammates one by one turn into enemies, Li San finally realizes that this so-called power is a gift from the abyss. The blade that can destroy all things will eventually point at him. And the nursery rhyme his sister hums has already echoed through a church a hundred years ago... This is a desperate gamble over human nature that spans time and space, with love as its sheath and hatred as its blade.
