In a world where portals open to unleash terrifying monsters known as Shadows, only Hunters stand between humanity and utter devastation. These Hunters level up by completing dungeons, gaining new skills, and enhancing their abilities. Among them is Lee Jun-seo, a low-ranked Hunter known for his submissive nature and mediocre skills. After a near-fatal encounter in a dangerous dungeon, he barely escapes with his life, only to awaken to an unfamiliar system the Shadow System giving him a second chance to rise above his former self. As he ascends with the Shadow System, Lee Jun-seo transforms from a forgettable Hunter to one of the most powerful beings in existence. However, with newfound powers come unforeseen dangers, as the system is tied to a mysterious shadowy figure who seeks to control him. Battling both the monsters in the dungeons and the demons within himself, Jun-seo must navigate a treacherous path where betrayal lurks in every corner. Unlike Sung Jin-Woo, Jun-seo is more enigmatic embodying the duality of a calm demeanor and explosive wrath. The balance between his hot and cold personality defines his relationships, drawing allies toward his magnetism while also making enemies wary of his unpredictable nature. The deeper he delves into the shadows, the more he learns about the dark secrets surrounding the dungeons, the Hunters, and his own past.