Skylar, a detective struggling with a fractured mind, is investigating a series of brutal murders marked by a distinctive modus operandi and signature behavior when the Deadly Seven System suddenly appears before him. In the next instant, he is torn away from the crime scene and thrown into a parallel world that closely resembles Earth. A world where the Sin Virus has spread for centuries, turning humans into monsters, grotesque manifestations of the seven deadly sins they once committed. In this world, Skylar is forced to live under a new fate. He becomes a Hunter, a Killer of the rare highest rank. Guided by the system, he carries out mission after mission to eradicate the Sinforged monsters, relying on his sharp detective instincts. Every step must be calculated, every judgment precise, for a single lapse into sin could condemn him to become a monster himself.