In a world where mysterious gates suddenly connect Earth to dungeons filled with monsters, some humans awaken supernatural abilities and become hunters. Sung Jinwoo is known as the weakest among them, forced to risk his life in low-level missions to support his family. After surviving an especially deadly dungeon, he discovers that a mysterious system allows him to increase his strength like a character in a video game, an ability normally impossible for other hunters. As he grows more powerful, Jinwoo draws the attention of guilds, foreign powers, and forces connected to the very origin of the gates.