Ten years ago, gates that connected our world to another dimension began to appear, leading to the rise of hunters who would traverse these gates to fight the magic beasts within. Sung Jin-woo, E-Rank hunter, is the weakest of them all.

Jin-woo and his party appear to have cleared a low-level dungeon, when a hidden path to an unfamiliar temple is revealed. There they encounter a set of commandments and a group of monsters that cause them absolute despair.

Jin-woo remains behind in the temple dungeon to save his few surviving party members, and with a swing from the god statue's blade, his life comes to an end, or so it seems, before he wakes up in a hospital bed.

Having entered the instance dungeon located inside the subway, Jin-woo levels up time and time again by fighting waves of magic beasts. As he gradually makes his way forward, he finds a long stairway leading deeper underground.

Jin-woo joins Hwang Dong-suk's party for a C-Rank dungeon. With temporary member Yoo Jin-ho, they defeat beasts. Jin-woo worries about no healer.

While the C-Rank dungeon raid by Jin-woo and the others seems to be progressing well, the moment they step into an area covered in mana stones with a sleeping dungeon boss, things take a wrong turn.

As Jin-woo continues his training, he completes a daily quest one day by doing more than the quest requires, and a key that leads to a certain item appears in front of him.

Jin-woo recaps the events of the story so far, from his humble beginnings as the Weakest Hunter of All Mankind to his newfound power and renewed purpose.

Jin-woo answers a Hunter's Association request to take part in the raid of a D-Rank dungeon, where he encounters a few familiar faces.

At the D-Rank raid, Jin-woo is reunited with four of the Cartenon Temple survivors. Together, they explore the dungeon with Kang Tae-shik and his men. After splitting up, they hear a scream, and then.

Jin-woo survives tragedy once again, but Woo Jin-chul warns him that Hwang Dong-soo, an S-Rank hunter, may be after his life. Determined to grow stronger, he and Jin-ho raid a succession of C-Rank dungeons, but they attract attention.

A surprise "job-change quest" appears for Jin-woo. Seeking strength, he accepts and enters, confronting endless foes. The final challenge, a knight, stirs memories of the Cartenon Temple.

Drained from endless battle, Jin-woo sees a phantom of his past self. To overcome his own past as the Weakest Hunter of All Mankind, he struggles to find a way to clear the job-change quest.