For 20 years, Hyeonseok battled monsters in another world, ultimately succeeding in saving it and being rewarded with a return to Earth. Reborn into his old life as a former deliveryman named Chanseok, he initially looks forward to enjoying modern comforts. However, he quickly realizes that Earth has changed drastically during his absence. Monsters now emerge from unpredictable Erosion Points, and individuals with special abilities are designated as Hunters to eliminate them.

Reluctantly, Chanseok decides to register as a Hunter, mainly to earn a stable income. Having already saved an entire world once before, he assumes facing this new threat should be relatively manageable.