In a world where Gates to other realms filled with monsters began appearing, certain people awakened as Hunters to protect humanity. Sung Jin-Woo was an E-rank Hunter, the weakest of all. Despite his weakness, Jin-Woo persisted, driven by the need to care for his comatose mother and younger sister. His life was a constant struggle, mocked by others for his lack of power.

One day, during a raid, Jin-Woo’s team stumbled upon a hidden double dungeon, a rare and dangerous anomaly. Trapped inside, they faced impossible trials, and one by one, his comrades fell. Gravely injured and facing death, Jin-Woo was offered a choice by a mysterious system: become the Player. With nothing left to lose, he accepted.

Jin-Woo awoke with new powers, like a video game character, able to level up and grow stronger. Keeping his abilities secret, he began soloing dungeons, gaining strength and skills far beyond what he had ever imagined. His reputation as the "World’s Weakest Hunter" began to fade as he took on challenges that even higher-ranked Hunters feared.

As Jin-Woo delved deeper into the dungeons, he uncovered the dark secrets behind the Gates and the cosmic war between powerful beings known as Rulers and Monarchs. The system that had chosen him was part of this battle, granting him the power to challenge these entities.

In a final, epic battle, Jin-Woo faced the Monarch of Destruction, unlocking his full potential and defeating the ancient being. With his victory, Jin-Woo was given the choice to return to Earth as a hero or continue his journey across realms. Choosing the latter, he stepped into the unknown, leaving behind the world that had once called him weak. His journey as a legend had only just begun.