In a world where evil spirits roam, Jeongwol has seen them since childhood and tried to live a normal life by ignoring them. However, he gets caught up in a mission for the "Disaster Management Department" and loses his life. But instead of dying, Jeongwol finds himself mysteriously alive, now bound by a contract with a black serpent named Sahyeon. This contract has granted him immortality, but he can't help but wonder—has he been blessed, or cursed?