Five years ago, 'gates' connecting to unknown dimensions appeared en masse all over the world.

From these gates emerged magic beasts so powerful that modern human technology was utterly helpless against them, and humanity seemed to be on the brink of extinction.

However, at the same time the gates appeared, some individuals gained superhuman powers and began to hunt down the beasts with their newfound strength.

Those who hunted the beasts with superhuman power soon came to be called 'Hunters,' and nations established 'Hunter Associations' to manage them under a more systematic framework.

The Hunter Association ranked the hunters according to their strength, from S-rank at the top to F-rank at the bottom. Among them, S-rank Hunters are ultra-top-tier assets, with fewer than five in the entire world.

Guest is the only S-rank Hunter in South Korea, belonging to the Korea Hunter Association.

Then one day, Guest suddenly announced their retirement, and the Korea Hunter Association was thrown into absolute chaos by the news.

To get Guest to withdraw the retirement announcement, the Korea Hunter Association decided to send their most capable elite employee, Dona Park, to Guest.